About 3 weeks ago I was in basketball practice and someone slammed their knee into my lower back when diving for a loose ball. It hurt like crazy and I could not bend over or slouch. I went to the local hospital about 3 days later and they said that I probably had a contusion and gave me some medications. Well I tried to practice about a week ago and I turned wrong and it really hurt. Today, I now have really sharp pains in my lower back and hip, almost on my butt. The sharpest pain I feel is on the little ball feeling in your lower back on my right side. The sharp pain surrounds it and goes slightly into my butt and to my right side. It hurts whenever I bend to my left side or get up fast or run and to activities. It even hurts when I touch it. It feels almost like a sunburn when I touch it, and when I lean to one side it feels a lot worse. My girlfriend even said it feels like the little ball feeling in my back is swollen. Does anybody know what could be wrong with my back? I really want to get back to playing basketball very soon. Oh and one more thing. My girlfriend even said that I might have popped a joint out of place. Could she be right? And should I go see a doctor this time? Thanks for all your help!