My knee has been "messed up" for a few weeks. I'm not bothered by pain in any part of my body, that comes with running track, but my left knee doesn't hurt, it feels more like it is dislocated. My knee almost always feels stiff, and I feel a lot of pressure. It sort of feels like someone is taking a rubber band and pulling my kneecap in a direction it isn't meant to go in. I would normally just wait for it to heal and not give it a second thought, but this isn't the first time I've had something "go out". About six months ago while playing fastpitch I threw my arm out, and it never seemed to heal- it still pops very loudly and hurts when I throw a softball. I'm only in middle school, is this something to be worried about?