Hi, I just got back to tennis after almost 10 yrs. (I am 63 yrs. old and active). My right knee has begun to feel tight behind the knee, my knee is a little swollen after a tennis lesson and there is soreness and just a little pain on the outer right side of my knee. A physical therapist told me I may have strained a labial ligament and perhaps have the start of arthritis or bursitis in the area. He suggested I rest the leg, ice it and take Advil. It does help a lot but then it comes back again now and then after a tennis clinic. Does this sound serious? I m afraid my days of getting back to tennis are numbered.