I have been playing soccer for 10 years now. It was about 2 1/2 years ago I was playing indoor when my knee slipped out of socket. I moved really quick to the right and it popped back in. Ever since then I have been wearing a knee brace thinking it will come out again. About 2 years ago it started giving me trouble. It does crack and pop a lot yet it hurts. I can just be sitting down and i get like a sharp pain in a straight line just on my right side of my knee. What do you think is wrong?