Have your urologist check you for kidney stenosis or floating kidney. you need to take a IVP with contrast while standing and also while laying down. This will tell if the kidney is working and may be moving crimping closed the uretha that causes kidney stone like pains. Very rare but it does happen. I had all the same negative tests you did until we checked for this and that is the problem I had. Can be fixed with laproscopic surgery to reattach the kidney to your back muscle. Good luck and let me know what they say.
Buckeye Joe