This is a problem on the outer side of your thigh. It's an inflammation of the iliotibial band. That's a thick band of tissue that spans from your hip to your shinbone. When this band becomes in inflamed, it can hurt.
This syndrome is caused by overuse. As you move your leg, the iliotibial band can rub against the bones of your hip and knee. Over time, that irritates it. Iliotibial band syndrome is common in cyclists and runners. Poor training habits may raise your risk. You're also more likely to develop it if the structure of your leg causes the band to rub.
For many people, iliotibial band syndrome causes knee pain. You feel it on the outer side of your knee. But you can feel pain anywhere along the length of this band, all the way up to your hip. The pain gets worse with activity, and feels better with rest.
Treatment depends on the severity of your symptoms. If the inflammation is mild, you may be able to treat it with rest, stretches and medications. If these aren't helpful, you may need to try other options. In very severe cases, the iliotibial band can be released with surgery. Your healthcare provider can create a plan that's right for you.