I hurt my knee while playing soccer a year ago?

a year and 2 monthes ago i partially tore my ACL and subluxated my knee cap but i didn't need surgery. My knee hurt very badly and im a travel soccer player. I took off for 1 season, then my knee was still hurting so i took off for another, then aanother. i missed 3 season! My knee still hurts when im going up and down steps and when i run, are in active for a long time( like sitting to watch a 2 hr show or siomething without moving my knee) im 14, we tried phyysical therapy, didnt work, we tried pills... still didn't work and every time we go back to the doctors they say the same thing.....ice it, go to PT and it'll feel better but you know what.... that never freakin works. my mom is fustrated because lately my whole leg has ben cramping up and i can't walk, well not my whole leg but i can't move my knee at ALL and my thigh gets really tight. MY knee also pops and gives out on me occasionally. Like i was walking to softball practice , carring my batting bag and stuffand i just fell randomly, then my knee really hurt but i sat on the ground for like 5 minutes, then my friend helped me up. My knee it horrible and i kinda wanna chop it off some ttimes ( not really chop it off though) what could be wrong with my knee still. ohhhh and my knee is kinda swollen and my knee caps slide out of place all the time, and ima girl and when i was doing yoga my knee cap popped out of place COMPLELTEly so i had my friend help me push it back in. =] please help mee!!!!!!!! WHAT COULD BE WRONG WITH MY KNEE!!!!!!!! WHAT SHOULD I DO!!!!