Epsom salts baths can work wonders! You could get your gait analysed by a qualified professional, e.g. sports podiatrist. You could get checked out by a St John Neuromuscular Therapist - they measure aspects of your body to check if you have differences in bone lengths, postural issues, muscle imbalances, etc. They are great at figuring out how to get rid of pain. My husband was getting a very sore knee from running and a visit to the NMT showed he has one leg shorter than the other and his body twists in one direction (probably from the way he sits playing guitar), plus a number of other postural problems and muscle imbalances. He now wears a small insert in one shoe, and was given exercises to do for the other issues.