The neuro. Dr. sent me to PT. and things got worse just as fast. They tried but it didn’t help at all. My left leg us really sore in back of my knee. It sounds like a bone popping but the Neuro. Dr. said it was a muscle. It only hurt once in while, but still popped. Now it pops all the time, just when walking. When I ride my stationary bike it pops a lot. If I set at my computer for a while my left leg is real stiff, and I can’t walk on it till I, move it around and it pops again. Any one like that or hear of it?