Severe hip pain on one side usually comes from one of a handful common conditions, and the location of the pain is the biggest clue to what’s going on. Left-sided hip pain isn’t inherently different from right-sided pain; the same structures can be affected on either side. What matters most is where exactly you feel it: the outside of the hip, deep in the groin, in the buttock, or radiating down the leg. Each pattern points to a different source.
Where You Feel the Pain Narrows the Cause
Hip pain falls into three broad zones: anterior (front/groin), lateral (outside), and posterior (back/buttock). Pain deep in the groin when you flex or rotate your leg often signals a problem inside the joint itself, like osteoarthritis or a labral tear. Pain on the outside of the hip, especially over the bony point you can feel when you press, typically comes from the tendons or fluid-filled sacs (bursae) surrounding the joint rather than the joint itself. Pain in the buttock that shoots down the leg may not originate in the hip at all; it can be referred from the lower back.
These zones overlap, which is part of why hip pain can be confusing. Osteoarthritis, for instance, usually starts as groin pain but can also cause symptoms on the outside of the hip. Spine problems and hip joint problems share so much territory that researchers use the term “hip-spine syndrome” to describe cases where both structures are involved and it’s genuinely hard to tell which one is responsible.
Greater Trochanteric Pain Syndrome
If your pain is on the outer side of your left hip, gets worse when you lie on that side at night, and aches more after walking or standing for a long time, the most likely culprit is greater trochanteric pain syndrome (GTPS). This umbrella term covers irritation of the tendons that attach your gluteal muscles to the hip bone, inflammation of the bursae that cushion those tendons, and tightness in the thick band of tissue (the IT band) running down the outside of your thigh.
GTPS pain tends to build gradually. It can be triggered by a sudden increase in activity, like starting a new running program or spending a full day on your feet after weeks of being sedentary. A fall onto the hip can set it off too. The pain often radiates from the outside of the hip down to the knee along the outer thigh. One reliable way to check at home: stand on just your left leg. If that reproduces your pain within 30 seconds, GTPS is very likely. Pressing firmly on the bony prominence on the outside of your hip is another test. If it’s so tender you flinch, that finding alone has an 83% chance of matching what an MRI would show.
Osteoarthritis
Osteoarthritis is the most common cause of deep, aching hip pain in people over 50, though it can start earlier. The cartilage lining the hip socket wears down over time, and the body responds by growing extra bone around the edges of the joint. The hallmark symptom is stiffness in the morning that loosens up within about 30 minutes, along with a deep ache in the groin that worsens with activity. Over months and years, the pain becomes more constant, and range of motion shrinks. Getting in and out of a car, putting on shoes, or climbing stairs may become noticeably harder.
Among adults 60 and older, roughly 14% report significant hip pain on most days. People who are less physically active report hip pain at higher rates (about 18%) compared to those who exercise regularly (about 13%), which reflects both the protective effect of movement and the fact that severe pain discourages activity in the first place.
Labral Tears and Impingement
The labrum is a ring of cartilage that lines the rim of your hip socket, helping to keep the ball of the femur seated properly. It can tear from a sports injury, repetitive motion, or abnormal bone shape. Femoroacetabular impingement, where extra bone growth around the hip joint pinches the labrum during movement, is a common precursor. Both conditions cause pain in the groin that gets worse when you flex your hip, like when you bring your knee toward your chest, sit for a long time, or get out of a chair. You might also feel a catching or locking sensation.
Labral tears and impingement tend to affect younger, more active people, though they can appear at any age. When the pain is severe enough to interfere with daily life and doesn’t respond to rest and physical therapy, hip arthroscopy is an option. Recovery from that procedure typically looks like this: crutches for one to two weeks, a brace for about three weeks, return to desk work in one to two weeks, general recovery around six weeks, and return to heavy exercise or sports around 12 weeks. Physical therapy after surgery can last anywhere from a few weeks to a few months.
Pain That Comes From Your Back
One of the most underrecognized causes of hip pain is the lumbar spine. Nerve compression from a bulging disc, spinal stenosis, or degenerative changes in the lower back can send pain directly into the hip, buttock, and leg. This referred pain can feel identical to pain originating in the hip joint. Some early research into this overlap found that patients who continued to have hip pain even after hip replacement surgery were actually suffering from lumbar spinal stenosis. Once their spinal condition was treated, the pain resolved.
Clues that your back might be the source include pain that radiates below the knee, numbness or tingling in the leg or foot, and pain that changes depending on your posture (worse when sitting, better when walking, or vice versa). If your hip has full range of motion without much pain but certain back positions reproduce your symptoms, the spine is the more likely origin.
Less Common but Serious Causes
Most hip pain is mechanical and not dangerous, but certain patterns warrant urgent attention. Septic arthritis, an infection inside the joint, causes severe pain that comes on fast, makes it nearly impossible to bear weight, and is usually accompanied by swelling, warmth over the joint, skin color changes, and fever. This is a medical emergency because the infection can permanently damage cartilage if not treated quickly.
Stress fractures of the hip bone can also cause intense pain, particularly in older adults with osteoporosis or in athletes who have rapidly increased their training volume. The pain is typically sharp, worsens with any weight-bearing, and doesn’t improve with rest over a few days. If your pain came on suddenly, is severe enough that you can’t walk, or is paired with fever, those are reasons to seek care right away rather than waiting it out.
What You Can Do at Home
For pain that isn’t accompanied by red flags, a few adjustments can make a meaningful difference. Sleep position matters a lot, especially with lateral hip pain. Sleeping on your back with a pillow under your knees, or on your unaffected side with a pillow between your knees, keeps your hips aligned and takes pressure off irritated tendons and bursae. Sleeping directly on the painful side compresses the very structures that are inflamed and almost always makes things worse.
Ice applied for 15 to 20 minutes several times a day can reduce inflammation in the first few days of a flare. Over-the-counter anti-inflammatory medications help with both pain and swelling. Beyond immediate relief, strengthening the muscles around the hip, particularly the gluteal muscles, is the most effective long-term strategy for most causes of hip pain. Exercises like clamshells, side-lying leg raises, and bridges target these muscles without putting excessive stress on the joint. Starting gently matters; pushing through sharp pain typically sets recovery back.
For GTPS specifically, studies have found that physical therapy produces results comparable to corticosteroid injections. A six-week course of targeted treatment brought the same improvements in pain, daily function, and medication use whether patients received injections or hands-on therapy. The advantage of the exercise-based approach is that it addresses the underlying weakness or imbalance rather than just calming inflammation temporarily.