Have they checked for “floating” kidney? They have to do supine and standing imaging to compare, to see if the kidney(s) drop down when standing ( > 5 cm of change). X-ray with contrast works for the imaging. This can cause significant pain and is very difficult to DX because no one thinks about it. I only know about it because my Dr. is thinking it might be an issue for me (I had my x-rays done last week). Look it up online and see if the symptoms match up. From what I have read the surgery to treat it (put the kidneys back in place and keep them there) is pretty easy and has great results. It seems to me it would totally be a connective tissue problem.