I agree with philnoir. As early as possible, try to see your doctor so you can undergo test that will help you know the probable cause of the pain you're feeling. Try to see a spinal or a joint pain specialist. I guess they are the one who can give you the best medical advice for this. I hope you'll get better soon!
No one here can tell you what this problem is.
You need to see a practitioner who can take a history and make a physical exam, and perhaps order some diagnostic tests. Only then can you expect a diagnosis.