Elite runner. have cam lesion on left femoral head and have always had trouble flexing as much as right and left si joint pain. is this why?

Could be..: Sacroiliac dysfunction can occur for a variety of reasons, and limited hip range of motion on one side be could be reason. A physical therapist with a special interest in runners that also has orthopedic manipulation skills could be a great resource for you. Do know that many patients have cam lesions and evidence of femoroacetabular impingement on x-rays but no symptoms or associated dysfunction.

Many possibilities: Your pain could be as a result of many different things. A thorough history and physical exam and possibly some laboratory and radiology exams are needed to determine the exact cause. Causes of pain may include: trauma (fracture, sprain, arthritis), infection, metabolic conditions (gout), musculoskeletal or biomechanical abnormality and neurologic conditions (neuropathy).