Left-sided hip pain is rarely caused by something unique to the left side. In most cases, the same conditions that affect any hip are responsible, and the pain shows up on the left because of how you move, sleep, or load that joint during daily life. Where exactly you feel the pain, whether it’s on the outside, in the groin, or deep in the buttock, is the most useful clue to what’s going on.
Location Matters More Than Side
Hip pain falls into three broad zones, and each one points to a different set of causes. Pain on the outside of your hip, over the bony prominence you can feel when you press your hand against your upper thigh, typically comes from the tendons and fluid-filled sacs in that area. Pain in the front of your hip or deep in the groin usually involves the joint itself or the muscles that flex your leg forward. And pain in the back of the hip or buttock often traces back to your lower spine, the sciatic nerve, or the muscles and tendons that attach near your sit bone.
Figuring out which zone your pain falls into is the single most helpful thing you can do before seeing a provider. Try pointing to the spot with one finger. If it’s on the side, read on about trochanteric pain. If it’s in the groin or front of the thigh, look at the joint-related causes below. If it wraps around to the buttock, the spine and nerve section will be most relevant.
Outer Hip Pain: Greater Trochanteric Pain Syndrome
The most common cause of pain on the outside of the hip is greater trochanteric pain syndrome (GTPS), a blanket term that covers irritation or degeneration of the gluteal tendons, inflammation of the bursa (a small cushioning sac), and friction from the thick band of tissue that runs down the outside of your thigh. It’s sometimes still called hip bursitis, though tendon problems are now recognized as the more frequent driver.
GTPS typically starts as a sharp or intense pain on the side of the hip that gradually settles into a persistent ache. You’ll notice it most when getting out of a chair or bed, climbing stairs, sitting for long stretches, or lying on the affected side at night. Walking with a limp, joint stiffness, and a catching or clicking sensation are also common. The pain can radiate down the outer thigh toward the knee, which sometimes leads people to think the knee itself is the problem.
Side-sleeping is a major contributor. If you always sleep on your left side, you compress the tendons and bursa against the bone for hours at a time. Sleeping with a pillow between your knees helps keep your hips aligned and takes pressure off that area. Sleeping on your back with a pillow under your knees is another option that reduces loading on both hips overnight.
Groin and Front Hip Pain
Pain felt deep in the groin or at the front of the hip usually originates inside or very close to the hip joint. In younger adults, the two most common culprits are labral tears and femoroacetabular impingement. In people over 50, osteoarthritis takes the lead.
Labral Tears
The labrum is a ring of cartilage that lines the socket of your hip joint, helping to seal it and keep the ball of the thighbone stable. When it tears, you may feel a deep, dull ache that sharpens with certain movements like pivoting, squatting, or exercise. Clicking or popping with hip movement is a hallmark sign. The pain often feels like it’s coming from deep inside your body, closer to bone than muscle, and it can radiate into the groin, lower back, or leg. Some people describe a sense of instability, as if the hip might give way.
Femoroacetabular Impingement
This happens when the shape of the ball or socket (or both) causes abnormal contact during movement. It’s one of the most common causes of hip pain in young adults and often coexists with labral tears. The pain tends to flare with activities that involve deep bending at the hip, like sitting in low chairs, squatting, or bringing your knee toward your chest.
Osteoarthritis
Hip osteoarthritis occurs most often in people 50 and older, though prior injuries, family history, obesity, or a hip that didn’t develop normally at birth can push it earlier. The classic pattern is groin pain that spreads toward the buttock or knee, worsens with vigorous activity, and feels stiffest in the morning or after sitting for a while. Over time, the pain becomes more frequent and can show up at rest or at night. You may notice a grinding sensation during movement, reduced range of motion, and a limp. Some people find the pain tracks with weather changes, worsening on rainy days.
Buttock and Posterior Hip Pain
Pain felt in the back of the hip or deep in the buttock often has nothing to do with the hip joint itself. The lower spine is the most common source. A herniated disc or other lumbar spine problem can compress or irritate a nerve root where it exits the spinal column, sending pain, numbness, or tingling down into the hip, buttock, and leg. This is called lumbar radiculopathy, and it can mimic hip joint pain convincingly.
Deep gluteal syndrome (sometimes called piriformis syndrome) involves entrapment of the sciatic nerve by the deep muscles of the buttock. It causes pain in the buttock that may radiate down the back of the leg. Sacroiliac joint dysfunction, where the joint connecting your spine to your pelvis becomes irritated, is another frequent cause of posterior hip pain. Hamstring tendon problems near the sit bone round out the list, especially in runners and people who do repetitive bending.
Why the Left Side Specifically
Most people who search this question assume something is wrong with the left hip in particular. In the vast majority of cases, the pain is one-sided simply because of asymmetry in how you use your body. Habitual side-sleeping on the left compresses the outer hip structures on that side. Crossing the left leg over the right while sitting loads the left hip differently. Favoring one leg when standing, carrying bags on one side, or a subtle difference in leg length can all shift more stress to one hip.
Previous injuries matter too. An old left knee or ankle injury may have changed your gait just enough to overload the left hip over months or years. Sports that involve dominant-side pivoting or kicking can create imbalances. The cause is almost always mechanical and behavioral rather than something uniquely wrong with the left side of your body.
Simple Movements That Help Pinpoint the Problem
A few basic movements can help you and your provider narrow down the source. Lying on your back, bend your left knee and hip to 90 degrees, then let the knee fall outward while gently pressing down. If this produces pain in the groin, the hip joint or labrum is likely involved. If it produces pain in the back of the hip or buttock, the sacroiliac joint may be the issue.
While lying flat, have someone gently roll your straightened leg side to side. If this reproduces sharp pain in the hip, it raises concern about a fracture or significant joint problem. Pressing directly on the bony point at the outside of your hip and reproducing your typical pain points strongly toward greater trochanteric pain syndrome. And if bending forward at the waist with straight legs sends pain down the back of your leg, a spine or nerve issue is more likely than a hip problem.
When Imaging Helps
A standard X-ray of the hip and pelvis is the appropriate first step for persistent hip pain. It can reveal osteoarthritis, fractures, bone abnormalities, and joint space narrowing. If the X-ray looks normal or doesn’t explain your symptoms, an MRI is typically the next step. MRI is particularly useful for detecting labral tears, tendon damage, bursitis, and early cartilage loss that X-rays miss. For suspected labral tears or impingement, a specialized MRI with contrast injected into the joint can improve accuracy.
Imaging isn’t always necessary right away. Many soft tissue problems like GTPS or mild muscle strains can be diagnosed based on your symptoms and a physical exam alone, especially if the pain is recent and clearly tied to activity or sleeping position.
Signs That Need Prompt Attention
Most left hip pain is manageable and not dangerous, but a few patterns warrant faster evaluation. If you can’t bear weight on the leg at all, you need same-day assessment to rule out a fracture. Hip pain accompanied by fever or feeling systemically unwell raises concern for infection. A new palpable mass near the hip should be evaluated with imaging.
The combination of hip or buttock pain with new numbness, tingling, or weakness in the legs, especially if paired with any change in bladder or bowel control or numbness in the groin area, can signal a compressed bundle of nerves at the base of the spine called cauda equina syndrome. This is rare but requires urgent assessment.