I injured my knee about 8 months ago by stepping the wrong way and twisting it a little. After a few months the swelling went away and I was feeling good. However, about two weeks ago the pain and swelling reappeared and haven't gone away. The swelling and pain aren't keeping me from playing tennis but I can't really run and quickly change directions. I can't server and volley either. I'm icing it and taking anti-inflammatory medication. I don't want to stop playing tennis completely but I'll take a few days off. What do you think is the problem and how should I deal with it?