It is usually the case that if something feels better with activity, the activity is probably not a problem. Things often feel better and sound better when movement pushes the fluid out of structures that are inflamed. The MRI will show any osteoarthritis in the hip and soft-tissue shit in the knee, if you really decide to spend the money on it. But is it necessary to know a precise diagnosis if it is not going to result in surgery and if the movement actually makes it feel better? Is it healing?