Hello, I see this was posted on the 5th of January, is it any better?
If you are still having this pain, then I suggest seeing a chiropractor, you may have some pinched nerve in your lower to mid back. He/she will take a couple of x-rays, study them and then go over the results with you. After a few adjustments you should start feeling better.
One thing I would like to add, if it is worse and you are nauseous or fever, I would go the ER, there is a slim chance it could be related to your appendix, but by now, if it is/was, you would have found out.
Hope you are doing better.