Welcome to the Pain Management Forum. I am glad that you found us and took the time to post....but sorry to hear about your undiagnosed pain.
We know how frustrating it is to have pain and no definitive explanation for it. My heart goes out to you. The CT Scan should have ruled out most conditions including stones and pyelonephritis as your physician determined.
Abdominal surgeries can leave you with adhesions (scar tissue) which can produce nasty pain that may not be similar to your previous abd pain. Adhesion pain use to be difficult to diagnosis and was often one of exclusion and based almost solely on clinical symptoms. However large facilities now have a newer MRI called a Cine-MRI. It is able to detect intraabdominal adhesions that the other MRIs were unable to detect.
One of the few treatments for adhesions is surgical removal...which in the past usually just produced more adhesions down the road. However there are some great new products on the market that decrease or limit the formation of these pain producing adhesions. I have heard some great success stories.
That said, you may still want to pursue possible kidney conditions and not assume that although everything was "normal" on the CT they did not miss something. It's your body and you know it best. So be assertive and request additional testing. You may also want to copy and paste your post on MedHelp's Kidney Disease/Disorders Forum. Here is the link:
If indeed you have chronic pain as suggested I encourage you to seek treatment that will at least allow you to be more comfortable. You may want to request a referral to a PMP. If they find a diagnosis at a later date you can always discontinue pain management therapy. At the least you deserve to be comfortable.
Please let us know how you are doing. I also encourage you to respond to other posts and be active in our community. We offer you our support and hope to hear from you again soon.