Doctors can't figure it out?

I've had left flank pain for about a year. Between now and then, I've had: bladder, kidney, and UTI infections. Blood in urine, nausea/vomiting/diarrhea, feverish and chills, blocked ureter (had nephrostomy tube for 2 months) and kidney stones. My urologist and nephrologist don't think it's kidney related. But it seems like it is. What is it and what should I do? I have ct scans with pain when nothing shows up. I'm not sexually active or anything. And I don't do drugs or drink.