I dont know what i have, but i fell on a bmx bike a couple months ago and it seems like i sprained my knee after a while it healed but im guessing not proper because i was playing catch with my freind and as i threw the ball i like turned my whole body and when i went back to throw the ball i threw it and fell on the floor it felt like my knee got out of placeand i got back up and 2 days later it felt good but what i notice is that if i sit on the floor and i can make the back of my leg touch the floor with my right but the left it hurts i cant do it and some times when i run it feels like my knee goes to the side or something can you please help or give me some good advice