What could a bad pain around hip be?

I'm an athlete and 2 days ago I got a stabbing pain on both sides of my hip, what is it?

• Well, I'm a teenage girl and I play soccer, I was out for about 2 weeks due to an injury to my elbow, when I returned I had a game and a couple days later we had a heavy practice full of running, we didn't stretch very well and I felt that I was going to be sore the next day. That night, well at dawn around 5 am I woke up to severe stabbing pain on both sides of my hips (left and right). The pain was like on the outer butt or thigh? I couldn't bend or move my legs because it hurt a lot. I went back to sleep and when I woke up again I couldn't get out of bed right away because it hurt where I'd gotten the cramp/ pain. I was limping for part of the day until the pain kind of subsided. The following night I woke up to the same pain at the same time but this time it was only on the right side. Once again when I woke up in the morning it hurt to walk and I was limping a bit until I KIND OF walked it off. Up until now both sides of my hip/outer butt hurt and I can't seem to remove the pain with any sort of stretching. P.S. : Also, I went to my soccer practice and when I was running around it didn't hurt very much. The pain seems to come when I go to sleep and sometimes in the morning when I sit for a long period of time. Does anyone have any idea as to what might be my problem and what I can do to relieve my pain especially when it comes at night/dawn?

• Answer:

  Cramping. After practice, stretch, and drink chocolate milk, eat a banana, do something to get potassium and calcium in your system. Remember to keep extremely hydrated.