I have an inner knee injury on my left leg which I got 7 weeks ago from playing tennis. It huts the most when I am sleeping, standing on only my left leg and when I get up from sitting a long time. It feels the best when I do stretches for it. My mobility is fairly good although not back to normal yet but it has improved each week but the pain has not gotten any better. However, I still can not bend that left knee to kneel on it. Any guesses what my injury could be and how to treat it? (Muscle, ligament, meniscus, or ?)