My Mother Has Pain Radiating Towards The Back In The

My mother has pain radiating towards the back in the lower right abdomen. Already performed ct scans and still no diagnosis. The doctors thought it could be a kidney stone, but they couldnt find one. Then they thought it could be ibs, but the meds for that aren't working. They found hypouretonephrosis, but they don't know what's causing it. Any suggestions?