I run track at school, and yesterday when I started running the upper part of my thigh suddenly started hurting REALLY bad, but i kept running on it until I couldn't take the pain anymore. It hurt when I started walking after that, but when I got home and took a shower everything was fine. Then today at practice I started running and it started hurting a lot again, and I could barley finish the workout. It hurts to move and do anything right now. I don't exactly know what I did, but what should I do to make it heal? or what??