I've been getting these random sharp pains on the outside of my tendons in my knee. I had x-rays done and nothing was shown. The doctor also bent and straightened my legs and he said that the kneecaps looked stable and he didn't see the need for an MRI. I have no idea what's wrong with them, I have full flexibility in them but sometimes when I'm sitting down or walking I get really sharp pains in them and they swell a little.