My Hip Hurts When I Lay On My Side: Causes and What to Do

Side-lying hip pain is one of the most common musculoskeletal complaints, and in most cases it traces back to a condition called greater trochanteric pain syndrome, or GTPS. For years doctors blamed an inflamed bursa (the fluid-filled cushion on the outer hip), but imaging studies have shifted the diagnosis: the real culprit is usually damage to the gluteal tendons that attach near that bony prominence on the side of your hip. Understanding the cause matters because the fix is different from what many people try first.

Why Side-Lying Makes It Worse

The greater trochanter is the hard bump you can feel on the outside of your upper thigh. When you lie on your side, that bony point bears a large share of your body weight against the mattress. Research measuring how pressure distributes across the body in different sleep positions found that the peak pressure at the greater trochanter in a side-lying position was roughly double the peak pressure at the sacrum when lying on your back.¹ That concentrated load compresses the tendons and bursae sandwiched between bone and mattress, irritating tissue that may already be inflamed or partially torn. This is why hip pain that barely registers during the day can become impossible to ignore when you roll onto your side at night.

The problem compounds over hours of sleep. Your body doesn’t shift position as often during deep sleep, so you can stay on the painful side long enough for the tissue to swell further. By morning the pain may radiate down the outer thigh, feel stiff when you first stand, and take a few minutes of walking before it settles. That pattern of nighttime aggravation and morning stiffness is so characteristic that it is one of the first things clinicians look for when suspecting GTPS.²

The Most Common Cause Is Not What You Think

If you search hip pain online, you will likely see the term “trochanteric bursitis” come up over and over. The idea is that the bursa on the side of the hip gets inflamed and that is the source of pain. This diagnosis was the default for decades, but MRI and ultrasound imaging have shown a different picture. Most people with lateral hip pain actually have gluteal tendinopathy, meaning the tendons of the gluteus medius and gluteus minimus muscles are degraded, partially torn, or both.³ Bursal inflammation does sometimes show up on imaging, but it tends to be a secondary finding rather than the main problem.

This distinction is not just academic. A person told they have bursitis might expect a cortisone shot and a quick resolution. A person with tendon degeneration needs a different approach: targeted strengthening over weeks to months, load management, and patience. Gluteal tendinopathy is now considered the primary local source of lateral hip pain, and it has a considerable negative influence on quality of life, particularly among postmenopausal women.⁴

Other Causes of Side-Lying Hip Pain

Gluteal tendinopathy may be the frontrunner, but it is not the only explanation. Several other conditions produce pain in the same area, and some of them coexist with tendon problems.

Snapping hip syndrome: A tight iliotibial band or the front edge of the gluteus maximus can catch on the greater trochanter and snap across it with certain movements. This produces a clicking or popping sensation along with pain on the outer hip, and lying on that side can bring it on or make it louder.⁵ The snapping itself is caused by the band sliding over the bony bump, and it can irritate the tissue underneath with enough repetition.⁶
Hip osteoarthritis: Arthritis inside the hip joint typically causes groin pain, but it can also radiate to the side or back of the hip. People with hip arthritis often have trouble sleeping on the affected side because the joint stiffens in one position. The clue is that arthritis pain tends to be deeper and may also bother you when you cross your legs or get in and out of a car.
Referred pain from the lumbar spine: Nerve irritation in the lower back can send pain down the buttock and along the outer hip in a pattern that mimics GTPS. If your hip pain gets worse with prolonged sitting, certain back movements, or coughing, the source may be your spine rather than the hip itself.
Hip labral tears: A tear in the ring of cartilage lining the hip socket usually causes a catching or locking sensation deep in the groin, but it can also produce a dull ache on the side of the hip, especially at night.

Because these conditions overlap in location and sometimes coexist, getting the right diagnosis often requires more than a self-assessment.

Who Is Most Likely to Develop It

Gluteal tendinopathy does not pick its targets randomly. The single biggest risk group is women between their mid-forties and early sixties. The reason is partly hormonal. After menopause, declining estrogen levels reduce tendon elasticity, alter collagen turnover, and impair the body’s ability to repair micro-damage in tendons.⁷ The gluteal tendons already carry heavy loads during walking and stair climbing, and when the tissue becomes less resilient, cumulative wear catches up faster.

Other risk factors include a wider pelvis (which changes the angle at which the tendons pull on the bone), a sedentary lifestyle that weakens the hip muscles, rapid increases in walking or running volume, and carrying extra body weight. People who habitually stand with their weight shifted to one hip, or who cross their legs tightly when sitting, place the gluteal tendons on a sustained stretch against the bone, which can accelerate irritation over time. Runners who suddenly bump up mileage or switch to hillier terrain sometimes develop it too, because downhill running loads the outer hip heavily.

How It Gets Diagnosed

Most of the time, a thorough physical exam is enough. Your doctor or physiotherapist will press on the greater trochanter, test the strength of your hip abductor muscles (the ones that move your leg outward), and try to reproduce the pain with specific movements like lying on the affected side or standing on one leg. Pain that is triggered by direct pressure over the outer hip and worsened by resisted hip abduction is highly suggestive of gluteal tendinopathy.

Imaging is not always necessary, but it helps when the diagnosis is unclear. Ultrasound can show tendon thickening and tears in real time, and MRI provides a detailed picture of both soft tissue and bone. Dynamic ultrasound, guided injections, and MRI all assist in differentiating the exact pathology behind lateral hip pain.⁸ Imaging becomes more important when initial treatment fails, because at that point you want to know whether there is a partial tear, a full-thickness tear, or something else entirely going on.

What You Can Do Tonight

If your hip wakes you at 2 a.m., the most immediate fix is changing the way you interact with the mattress. A few practical adjustments can reduce pressure on the trochanter enough to let you sleep.

Sleep on the unaffected side: Place a pillow between your knees and another under your top arm. The knee pillow keeps your pelvis level so the sore hip’s tendons are not stretched across the bone. Without it, the top leg drops toward the mattress and the tendon gets compressed.
Try sleeping on your back: If you can train yourself into it, back-lying eliminates trochanteric pressure altogether. A pillow under the knees takes strain off the lower back and makes this position easier to maintain.
Upgrade or adjust your mattress: A too-firm mattress concentrates pressure right on the bony point. Research has shown that mattress material affects peak body pressure, with latex reducing pressure peaks on the torso and hips compared to standard polyurethane foam.⁹ If a new mattress is not in the budget, a foam topper in the range of three to four inches can make a meaningful difference. On the other hand, a mattress that is too soft lets the hip sink in so far that the spine bends laterally, creating a different set of problems.
Use a mattress with adjustable firmness: For people with pressure-related pain, increasing the internal air pressure of an air-adjustable mattress in the lateral position can help reduce the maximum pressure at the greater trochanter.¹

Ice or a cold pack on the outer hip for ten to fifteen minutes before bed can also dull the pain enough to fall asleep. Anti-inflammatory medication like ibuprofen taken with dinner sometimes helps people get through the night, but it is treating the symptom, not the cause, and long-term use carries its own risks.

The Case for Targeted Exercise

The single most effective long-term treatment for gluteal tendinopathy is a structured exercise program that progressively loads the gluteal tendons. This is not the same as generic stretching. In fact, aggressive hip stretching can make matters worse by compressing the tendon against the bone. What works is a graduated strengthening program that starts with isometric holds (contracting the muscle without moving the joint), progresses to slow, controlled movements like side-lying leg raises and bridges, and eventually builds toward heavier resistance exercises like single-leg squats and step-ups.

A meta-analysis of exercise-based interventions for gluteal tendinopathy found that exercise was clearly superior to minimal treatment for improving function, both in the short term and the long term.¹⁰ The improvements were not just statistical; they translated to meaningful gains in activities like walking, climbing stairs, and sleeping on the affected side. Most programs run for eight to twelve weeks before patients see substantial improvement, and many people continue a maintenance routine afterward to prevent recurrence.

The tricky part is that people in pain tend to rest and avoid loading the hip, which leads to further tendon weakening and more pain. A physiotherapist who understands tendon loading principles can help you find the right starting intensity, one that produces a manageable level of discomfort during the exercise but does not leave the hip flaring for hours afterward. If you are waking up in more pain the morning after your exercises, the load was probably too high.

Movements to Avoid While Recovering

While you are building up tendon strength, certain positions and movements add compressive load to the gluteal tendons in ways that work against your recovery. The big ones are worth knowing because many of them feel instinctively like they should help.

Stretching the outer hip: Pulling the knee across the body or sitting in a deep cross-legged position presses the tendon hard against the trochanter. People do this because the area feels tight, but the tightness is usually from irritation, not shortness, and stretching aggravates it.
Standing on one leg with the hip dropped: Leaning into one hip while waiting in line or brushing your teeth puts the tendon on stretch under load. Try to stand with equal weight on both feet.
Sitting with legs tightly crossed: This is the seated equivalent of the hip-drop stance. It compresses the tendons for as long as you hold the position.
Going up or down stairs excessively: Stairs load the gluteals heavily. You do not need to avoid them entirely, but deliberately adding stair workouts while the tendon is reactive is counterproductive.

These modifications are temporary. Once the tendon has adapted to progressive loading and the pain has settled, you can gradually return to all normal activities.

Injections and Other Medical Options

When exercise alone is not enough, or when the pain is too severe to start an exercise program, several medical treatments can help bridge the gap.

Corticosteroid injections have been the go-to for decades. They are effective at reducing pain quickly, often within days, but the relief tends to be short-lived. Multiple studies have shown that corticosteroid benefits fade after a few months, and repeated injections may actually weaken the tendon over time. Platelet-rich plasma (PRP) injections have emerged as an alternative. In a randomized trial of patients with GTPS, those who received ultrasound-guided PRP had significantly better pain scores and hip function at six months compared to those who received corticosteroid injections.¹¹ PRP takes longer to kick in, sometimes several weeks, but the improvement appears to last longer without the regression seen with steroids.

Extracorporeal shock wave therapy (ESWT) is another option with growing evidence behind it. This involves applying acoustic pulses to the painful area, which is thought to stimulate healing in the tendon. One randomized trial found that focused shock wave therapy produced significantly greater pain reduction than ultrasound therapy at both two months and six months.¹² Separate research confirmed that shock wave therapy is an effective treatment for GTPS overall.¹³ A trial comparing shock wave therapy with therapeutic exercise found that both approaches led to progressive pain reduction over time, with no significant difference between the two.¹⁴ That last finding is actually reassuring: it suggests that exercise alone, when done properly, can match the results of a more expensive treatment. But for people who cannot tolerate an exercise program initially, shock wave therapy offers a way to reduce pain enough to get moving.

Surgery is rarely necessary and is typically reserved for full-thickness gluteal tendon tears that have not responded to months of conservative care. When it is done, the procedure involves repairing the torn tendon back to the bone, sometimes with the help of anchors. Most people never reach this point.

When to See a Doctor

Not all hip pain on the side requires a medical visit. If the pain is mild, recently started, and clearly tied to a change in activity or sleeping position, trying the home measures described above for a few weeks is reasonable. But certain patterns warrant professional evaluation sooner.

Pain that wakes you every night: Persistent sleep disruption affects everything from mood to immune function. If position changes and over-the-counter medication are not buying you sleep, get it assessed.
Pain that has lasted more than six weeks: Tendinopathy that has been brewing for over a month is unlikely to resolve on its own without a targeted loading program. A physiotherapist can design one and rule out other causes.
Hip weakness or giving way: If the hip feels unstable when you walk, or you notice a limp developing, the tendon may be more damaged than a typical overuse case.
Groin pain, fever, or sudden onset: Pain in the groin rather than the outer hip could indicate a joint problem or, rarely, an infection. Fever paired with hip pain is a red flag that needs same-day evaluation.

How Hormones Fit Into the Picture

The connection between estrogen and tendon health deserves special attention because it explains why so many women in their late forties through sixties develop lateral hip pain for the first time. Estrogen receptors exist in tendon tissue, and the hormone plays a role in maintaining collagen quality and the tendon’s ability to repair micro-damage from everyday use. A systematic review found that estrogen deficiency after menopause is associated with reduced tendon elasticity, altered load transfer, and impaired healing capacity.⁷

This does not mean hormone replacement therapy is a treatment for gluteal tendinopathy; the evidence is not there yet for that specific application. But it does mean that if you are a woman approaching or past menopause and you develop new lateral hip pain, the condition is not a sign that something has gone structurally wrong in an alarming way. Your tendons are adapting to a new hormonal environment, and with the right loading strategy, they can regain much of their tolerance. Women in this demographic who begin a progressive strengthening program tend to respond well, even if progress feels slower than they would like.

The Mattress Question in More Detail

People with lateral hip pain often become obsessed with their mattress, and that instinct is not wrong. The foam resilience of a mattress directly influences how body pressure is distributed across the surface.¹⁵ But the answer is not always “softer is better.” A mattress that is too soft allows the hip to sink until the pelvis tilts, which can strain the lower back and put the spine in a curved position all night. A mattress that is too firm concentrates all the pressure on the trochanter.

The sweet spot depends on your body weight, hip width, and shoulder width. Broader-hipped people generally need more give in the hip zone so the spine stays neutral. If your current mattress is on the firm side and you do not want to replace it, a medium-density foam or latex topper can add enough cushion at the hip without turning the whole bed into a hammock. Memory foam conforms well but retains heat; latex tends to be cooler and more responsive. The mattress material comparison study noted that latex reduced peak body pressure on the torso and buttocks compared to standard polyurethane foam, which is worth considering if you are shopping.⁹

One practical tip that costs nothing: if you sleep on your side, let your bottom arm extend forward rather than folding it under your body. This shifts some weight onto the shoulder and ribcage area and reduces the proportion borne by the hip. Pairing that with a thick pillow between the knees keeps the pelvis level and the tendons in a neutral, uncompressed position.

1
PubMed Central. Relationship between mattress internal air pressure and interface pressure distribution in the lateral position
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PubMed Central. Greater trochanteric pain syndrome: a review of diagnosis and management in general practice
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PubMed. MRI and US of gluteal tendinopathy in greater trochanteric pain syndrome
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Journal of Orthopaedic & Sports Physical Therapy. Gluteal Tendinopathy: Integrating Pathomechanics and Clinical Features in Its Management
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PubMed Central. Endoscopic Treatment of Recurred External Snapping Hip After Endoscopic Iliotibial Band Release
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PubMed. Endoscopic iliotibial band release for external snapping hip syndrome
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Muscles, Ligaments and Tendons Journal. Postmenopausal estrogen deficiency and tendon degeneration: a systematic review
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PubMed Central. Pathogenesis and contemporary diagnoses for lateral hip pain: a scoping review
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PubMed Central. Effects of Mattress Material on Body Pressure Profiles in Different Sleeping Postures
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PubMed Central. Effects of exercise-based interventions on gluteal tendinopathy. Systematic review with meta-analysis
11
PubMed Central. Ultrasound-guided Platelet-rich Plasma Application Versus Corticosteroid Injections for the Treatment of Greater Trochanteric Pain Syndrome: A Prospective Controlled Randomized Comparative Clinical Study
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PubMed. Focused extracorporeal shock wave therapy for greater trochanteric pain syndrome with gluteal tendinopathy: a randomized controlled trial
13
PubMed. Low-energy extracorporeal shock wave therapy as a treatment for greater trochanteric pain syndrome
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PubMed Central. Shock Waves and Therapeutic Exercise in Greater Trochanteric Pain Syndrome: A Prospective Randomized Clinical Trial with Cross-Over
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Advanced Materials Research. Study on Resilience of Mattress Foam and Body Pressure Distribution Characteristic of Mattress