I was working out today, agility and jumping drills. I landed fine, I thought, but as I kept doing the workouts my right knee started hurting more and more. I called it quits after there was a sharp pain under my knee cap and then I tried walking it off. There then was some burning and the pain was only existent when I jumped or moved while bouncing. I've heard of ACL tears where you don't feel it until 4 or 5 days later, and I was wondering if this could be a either a ligament strain or possible tear of the ACL. I am 16, and very active in a rigorous fighting sport. When I got home, the pain was only there when i walked out straightened my leg quickly. PLEASE give me some input. I need to know about some possibilities before i consider going to the doctor's.