What Causes Pain In Hip Joint?

With in the past week I have developed a pain in my right hip, up near the ball and socket. The past 2 days it have been unbearable. It doesnt hurt all the time. I know what mucle pain feels like and it doesnt burn or anything. It feels like some one is sticking my hip with a knife. Also i dont know if this has anything to do with it but here lately i have been having groin pains as well.