My hip is so sore? i thought it would be a kidney infection but...?

its on my hip not in my lower back, i feel like i can't move my leg or its going to hurt. i know this must sound strange, but does anyone have any diagnosis as to what it can be? it kind of feels like a pulled muscle or something? it comes and goes now and again and when i walk i feel like i have to walk weirdly and lopsided-ish if you could recommend a pain reliever? becaus i'm doing the junior cert and can't really afford to be in pain haha.-thanks in advance