Sorry about the half mini booty in this pic. Need help about pain in my back/ hip area

So for some reason yesterday I woke up and and noticed that my back / hip felt bruised. The first thought was that I hit it with something so I didn't pay it no mind. Honestly I'm so bony that I've hit my back agains a wall slightly and its created a bruised feeling in the back bones for a few days. However today I woke up and it still feels bruised. Not when slightly touched but if you press a little into it, it hurts like a bruise and its not right on my bony hip bones. It's actually behind them in that area I circled. I'm scared it could be something more serious. Has anyone had this problem before?