Pain isolated to one buttock almost always originates from a structure near the buttock rather than from the gluteal muscles themselves. The lower spine, the sacroiliac joint, deep hip rotators, and tendons anchored to the pelvis are the most frequent culprits. Whether the pain is on the left or right side rarely changes the list of possible causes; anatomy is essentially symmetrical, and which cheek hurts usually just reflects which side is being compressed, strained, or irritated. What does matter is the character of the pain, what makes it worse, and whether it travels down your leg.
A Herniated Disc in the Lower Back
The single most common spine-related explanation for one-sided buttock pain is a lumbar disc herniation, where the soft center of a spinal disc bulges out and presses on a nearby nerve root. A 2025 study of 321 patients with a single-level disc herniation found that roughly three out of four reported buttock pain, and it was a common complaint whether the herniation sat at the L3-4, L4-5, or L5-S1 level.1PubMed. Buttock pain in lumbar disc herniation: clinical characteristics, risk factors, and surgical outcomes That’s a strikingly high rate, and it means many people whose pain seems purely “in the butt” actually have a problem in their spine.
The telltale clue is often radiation. If the ache starts deep in one buttock and shoots or tingles down the back of your thigh, that pattern strongly suggests a nerve root in the lower back is involved. Bending forward, coughing, or sneezing can make the pain spike. But disc herniations don’t always produce leg symptoms; sometimes the buttock ache is the main or only complaint, which is why this cause gets missed.
Piriformis Syndrome and Deep Gluteal Syndrome
The piriformis is a small, flat muscle buried deep in the buttock that runs from the sacrum to the top of the thigh bone. When it goes into spasm, swells, or has an unusual anatomical relationship with the sciatic nerve, it can compress that nerve and produce pain that mimics a disc herniation. This is piriformis syndrome, and it’s frequently overlooked because no single imaging test reliably confirms it.2PubMed Central. Piriformis Syndrome Is Often Overlooked as a Cause of Gluteal Pain and Sciatica: Diagnostic Challenges and the Role of Imaging-A Narrative Review
The classic presentation involves buttock pain that gets worse when you sit, tenderness near the greater sciatic notch (the bony landmark deep in the buttock), pain on any movement that stretches or contracts the piriformis, and limited straight-leg raising.3PubMed. Four symptoms define the piriformis syndrome: an updated systematic review of its clinical features In practice, though, the sciatic nerve can be pinched by structures other than the piriformis, including scar tissue, the obturator internus muscle, or even fibrous bands in the deep gluteal space.4PubMed. The endoscopic treatment of sciatic nerve entrapment/deep gluteal syndrome The broader term “deep gluteal syndrome” captures all of these entrapment scenarios.
Diagnosis often relies on a combination of clinical tests and the process of ruling out spinal causes. One validated test involves flexing the hip, pulling it inward, and internally rotating it; a positive response reproduces the patient’s familiar buttock pain.5PubMed. Piriformis syndrome: diagnosis, treatment, and outcome–a 10-year study First-line treatment follows the same playbook as general sciatica management: physiotherapy, stretching, and activity modification.6PubMed. A systematic review of conservative and surgical treatments for deep gluteal syndrome
Sacroiliac Joint Dysfunction
The sacroiliac (SI) joint sits where the base of the spine meets the pelvis, right behind the buttock. When this joint becomes inflamed or moves abnormally, the pain tends to concentrate on one side of the low back and buttock, often right over the dimple above the hip.7PubMed. Sacroiliac joint dysfunction: pathophysiology, diagnosis, and treatment It can feel deep and achy, and it usually worsens when you stand on the affected leg, climb stairs, or roll over in bed.
SI joint problems are especially common after pregnancy, after a fall onto one side, or in people with asymmetric movement patterns. Unlike disc-related pain, SI joint pain rarely shoots all the way below the knee. It tends to stay in the buttock and upper thigh. The overlap with piriformis syndrome and lumbar disc problems is large enough that clinicians sometimes use a diagnostic injection directly into the SI joint to confirm it as the source.
Hamstring and Gluteal Tendon Problems
Two tendon-related conditions deserve separate mention because they’re common and easily confused with deeper problems.
Proximal hamstring tendinopathy produces deep, localized pain right at the bottom of the buttock, over the “sit bone” (ischial tuberosity).8PubMed. Proximal Hamstring Tendinopathy: Clinical Aspects of Assessment and Management It’s triggered by activities that load the hamstring origin: prolonged sitting on hard surfaces, squatting, uphill walking, and running.9PubMed Central. Treatment of Proximal Hamstring Tendinopathy with Individualized Physiotherapy: A Clinical Commentary Despite the association with running, this condition hits sedentary people too, especially those who sit for long stretches on firm chairs. The pain tends to be very point-specific; if you can put your finger exactly where it hurts, and it’s directly on the sit bone, this is a strong suspect.
Gluteal tendinopathy, on the other hand, centers on the side of the hip and upper outer buttock. The tendons of the gluteus medius and minimus attach to the bony bump at the outer hip (the greater trochanter), and when they become irritated, the pain can spread into the buttock.10PubMed. Gluteal Tendinopathy: A Review of Mechanisms, Assessment and Management This condition used to be called “trochanteric bursitis,” but imaging and surgical studies have shown that the tendon, not the bursa, is usually the real problem.11PubMed Central. Exercise and load modification versus corticosteroid injection versus ‘wait and see’ for persistent gluteus medius/minimus tendinopathy (the LEAP trial): a protocol for a randomised clinical trial It tends to flare when you lie on the affected side at night or stand with your weight shifted onto one leg.
Myofascial Trigger Points
Sometimes the pain doesn’t come from a joint, disc, or tendon at all but from a knot-like area in the muscle itself. Myofascial trigger points are hypersensitive spots within a taut band of muscle that can produce local and referred pain. An international expert consensus defined them by three features: a taut band, a tender spot within it, and referred pain that can feel like a deep ache, dull pressure, tingling, or burning in a distant area.12Pain Medicine. International Consensus on Diagnostic Criteria and Clinical Considerations of Myofascial Trigger Points: A Delphi Study
In the context of buttock pain, trigger points in the gluteus medius, gluteus minimus, or even the quadratus lumborum (a deep back muscle) can send pain into the buttock on one side. These trigger points are commonly found in people with chronic low back pain, where they actively contribute to the overall pain picture.13Pain Medicine. Myofascial Trigger Points, Pain, Disability, and Sleep Quality in Patients with Chronic Nonspecific Low Back Pain The frustrating part is that trigger points don’t show up on MRI or X-ray, so they’re diagnosed by feel. A physical therapist or clinician presses into the muscle, finds the taut band, and reproduces the familiar pain pattern. Treatment involves manual pressure release, dry needling, or targeted stretching.
Everyday Habits That Fuel One-Sided Pain
Before looking for exotic diagnoses, it’s worth examining your daily routine. Several mundane habits can create or worsen unilateral buttock pain.
Sitting on a wallet is the most infamous example. When a thick wallet sits in your back pocket, it tilts the pelvis, puts uneven pressure on the piriformis, and can irritate the sciatic nerve. The condition even has a name: “wallet neuritis” or “back-pocket sciatica.” Research has noted that the posture of the pelvis and lower spine gets compromised with a thick wallet, mounting uneven pressure on pelvic muscles, discs, and nerves, and that even a relatively small wallet can be enough to generate symptoms.14PubMed Central. Wallet Neuritis – An Example of Peripheral Sensitization The fix is simple: move it to a front pocket or a bag.
Leg-length discrepancy is another mechanical factor that gets discussed but is surprisingly hard to pin down clinically. One leg being shorter than the other shifts your pelvis and changes how forces travel through the buttock and hip. Whether this actually causes pain is debated; a direct connection to back pain is questionable based on current evidence, though changes in leg length do place extra mechanical stress on soft tissues.15PubMed Central. Leg Length Discrepancy- Treatment Indications and Strategies In other words, it might contribute to buttock pain in some people, but it’s rarely the sole cause.
Prolonged sitting on hard or uneven surfaces, crossing the same leg repeatedly, and sleeping in the fetal position on one side can all perpetuate irritation in the piriformis, SI joint, or hamstring origin. These habits are worth inventorying because they’re modifiable and often the difference between a problem that resolves and one that lingers.
Less Common Causes Worth Knowing About
Most one-sided buttock pain traces back to the musculoskeletal causes above. But a handful of less common conditions can present the same way and deserve awareness, especially if standard treatments aren’t working.
Inflammatory spinal conditions like axial spondyloarthritis (which includes ankylosing spondylitis) can debut as buttock pain, particularly in younger adults. One case report described a man in his twenties whose gluteal pain was initially attributed to piriformis syndrome; only after standard treatment failed was he correctly diagnosed with axial spondyloarthritis.16PubMed Central. A Case Report of Piriformis Syndrome With Axial Spondyloarthritis in a Young Male Patient Presenting With Buttock Pain In another case, a military athlete presented with buttock pain as the main symptom of ankylosing spondylitis, without the expected spinal stiffness.17JOSPT Cases. Ankylosing Spondylitis Presenting as Buttock Pain in a Military Tactical Athlete: A Case Report The hallmark clue is pain that improves with movement and worsens with rest, especially morning stiffness lasting more than 30 minutes.
Sacral stress fractures can cause insidious buttock and low-back pain, particularly in distance runners and people with reduced bone density. A case report documented a young long-distance runner who developed right-sided buttock pain without any trauma after a marathon; MRI revealed extensive bone marrow swelling in the sacrum consistent with a stress fracture.18PubMed Central. Sacral stress fracture in a young-adult, long-distance runner: an underestimated cause of low back pain These fractures don’t show up on regular X-rays, which is why they’re frequently missed.
Vascular insufficiency is rare but real. Buttock claudication, where the buttock cramps during exercise and eases with rest, usually signals blockage in the arteries feeding the gluteal muscles. It’s most often caused by obstruction in the aorta or common iliac artery, though isolated stenosis of the gluteal artery itself has been reported.19PubMed. Buttock claudication from isolated stenosis of the gluteal artery If your buttock pain only appears during walking or exercise and stops within minutes of resting, and especially if you have cardiovascular risk factors, this deserves evaluation.
In women, endometriosis can occasionally grow along or around the sciatic nerve, producing cyclical buttock and leg pain that worsens with menstruation. Case reports describe endometriotic lesions near the greater sciatic foramen compressing the sciatic nerve and causing progressive weakness alongside pain.20PubMed Central. Sciatic nerve endometriosis – The correct approach matters: A case report This is uncommon enough that it’s rarely considered early, but if buttock pain fluctuates with the menstrual cycle, it’s worth mentioning to a clinician.
Visceral problems can refer pain to the buttock in unusual ways. A case report described a 40-year-old man whose gluteal abscess turned out to be the first sign of diverticular disease, an intestinal condition that had burrowed through tissue to present in the buttock.21PubMed Central. A diverticular ‘pain in the bottom’ These scenarios are rare but illustrate that the source of buttock pain isn’t always musculoskeletal.
Injection Injuries and Iatrogenic Causes
If your left buttock pain started after a gluteal injection, the needle itself might be the problem. The sciatic nerve is the most commonly injured nerve from intramuscular injections because of its large size and the buttock’s popularity as an injection site.22PubMed Central. Iatrogenic Injury to the Sciatic Nerve due to Intramuscular Injection: A Case Report A misplaced injection can cause immediate burning pain, weakness in the foot, or numbness down the leg. This risk is one reason healthcare providers are trained to use the upper outer quadrant of the buttock and why many injections have shifted to other sites. If symptoms appeared right after a shot, that timeline is diagnostically important and should be reported to your provider.
When to Get Evaluated Urgently
Most buttock pain is not dangerous. It’s annoying and sometimes debilitating, but it resolves with time, stretching, and activity changes. There are a few scenarios, however, where you should seek medical attention without delay.
Cauda equina syndrome is the big emergency. It occurs when the bundle of nerves at the base of the spinal cord gets compressed, usually by a massive disc herniation, and it produces a combination of sensory loss, motor weakness, and problems with bladder or bowel control.23PubMed. Evaluation and Management of Cauda Equina Syndrome Numbness around the groin or inner thighs (sometimes called “saddle anesthesia”), difficulty starting or stopping urination, or sudden loss of bowel control alongside buttock and leg pain all warrant an emergency room visit. This condition requires surgery within hours to prevent permanent nerve damage.
Outside of cauda equina syndrome, other signs that warrant prompt evaluation include progressive leg weakness, unexplained weight loss paired with deep buttock pain, pain that worsens at night and isn’t related to position, and fevers with buttock swelling or redness. A buttock abscess, for instance, can develop from a skin infection or, as noted earlier, from internal disease tracking outward, and it needs drainage and antibiotics.
Why “Left” Versus “Right” Usually Doesn’t Matter
People often wonder whether left-sided buttock pain points to something different than right-sided pain. In the vast majority of cases, it doesn’t. The structures on both sides are mirror images of each other, and the same conditions affect both. A disc herniation at L5-S1 will press on the left nerve root if it bulges left, and the right root if it bulges right. Piriformis syndrome can develop on either side depending on which muscle is tighter or which sciatic nerve has an unusual course through the muscle.
There are a few narrow exceptions. Internal organs that sit on one side of the body can theoretically refer pain asymmetrically. The sigmoid colon, for example, sits on the left side, and severe left-sided diverticulitis can occasionally produce referred discomfort in the left buttock or hip. But this pattern is unusual enough that you shouldn’t assume your left buttock pain is a bowel problem. If the pain behaves like a musculoskeletal issue, worsening with movement, sitting, or certain positions, the cause is almost certainly musculoskeletal. The side simply tells your doctor which nerve root, joint, or muscle to investigate.
Ischiogluteal Bursitis and the “Weaver’s Bottom”
One condition that creates a distinctive pattern of one-sided buttock pain is ischiogluteal bursitis, historically called “weaver’s bottom” because it plagued people who sat on hard surfaces for long hours. The bursa over the ischial tuberosity (sit bone) becomes inflamed, producing pain exactly where the buttock meets the chair. A case report of a female runner with pelvic involvement listed ischiogluteal bursitis in the differential diagnosis alongside hamstring syndrome, both of which center on the same bony landmark but involve different tissues.24PubMed Central. Differential diagnosis of deep gluteal pain in a female runner with pelvic involvement: a case report
The distinction matters for treatment. Bursitis responds well to anti-inflammatory measures, cushioned seating, and sometimes a corticosteroid injection into the bursa. Hamstring tendinopathy, by contrast, tends to worsen with cortisone injections and instead responds to gradual loading exercises. Since both conditions produce pain in the same spot, a clinician often differentiates them by testing hamstring strength and checking whether compressing the area versus loading the tendon changes the pain.
For anyone dealing with persistent one-sided buttock pain, the most useful first step is noting exactly where it hurts, what makes it better or worse, and whether it travels. That information narrows the list considerably and helps a clinician zero in on the right diagnosis faster than imaging alone.