So yesterday morning, I noticed that my knee was slightly more painful than it usually is. I decided to wait it out, figuring that it would go away, and it didn't. Now, every time I either extend or contract (squeeze) my left leg together, the left part of my back knee hurts and feels like it pops. It isn't my kneecap or anything really under my kneecap, it feels like a muscle or a tendon in the back left part of my knee area of my leg that pops and hurts if I fully extend my leg.
BTW, it could be because I play competitive tennis and I run 2.5-3 miles 3 times a week.
Does anyone have any tips?