question: so I was doing gymnastics 2 days ago for P.E then the back of my knee started hurting but it ignored it because i thought it would go away later but when I got home it still hurts so I put ice packs on it for 10-20 minutes then I was massaging the back of knee then all the sudden I feel this movable ball behind my knee. I suspect it's a bakers cyst but it's doesn't as much as yesterday and I could see no swelling, and now I'm really confused