I just finished playin ball for 3-4 hours, and my left knee is killin me. I've narrowed the pain down, its from the bottom under portion of my knee cap. It started hurting about 2-3 months ago when I was playn football. It hurts only after/during i play sports, and randomly when im in a car or driving. It was fine before, and i dont recall any serious injuries to that knee. Any input before i head to the clinic?