Excruciating Pain In Upper Back, Below Breast. Had Surgery For Decompression Of Nerves. No Help With Antibiotics. Suggestions?

I have excruciating pain on the upper right side of my back and front under by breast. Whenever I move or stretch my right leg I feel these pain and a feel that my right rib is pushing up my breast. I just had surgery of decompression of nerves on L5 . X-ray showed shadow in my right lung during the pre-op but was approved for surgery. The pain continued and was given antibiotics by the hospitalist. Another x-ray and Ct Scan was done and the shadow was still there. Discharged from my back surgery and given antiobiotics to take for the back pain. The hospitalist still thinks or suspects it to be pneumonia.. I have finished the antibiotics and still feeling the back pain. I feel it morewhen lying down, seem to be less when up and sitting.
what should be my next step so I can get rid of this back pain so I can concentrate in getting back the strength on both my legs which were affected due to compressed nerves. Thank for any advice you can give me.