I'm 20 yrs old...and I have leg pain in knee joint (left leg) what's the reason for that pain.? Can you tell me sir.?

Knee pain. 20 has L knee pain and want to know reason. Asks: An you tell me sir? ANS: Yes if I can talk to you by having you do 2nd opinion with me now. Otherwise see someone and tell them more. And then have them examine you.