Jane UK…. The only thing I can suggest is have and MRI with/wo contrast done instead of CT. When ever I’ve had MRI’s versus CT Scans a more indept view of what could be going on. In my case we found a small soft tissue tumor pressing on my spinal roots causing significant pain to lower back,side and stomach. Once that was found I had IMRT 3-D radiation to that tumor and it’s been over a year and no problems so far. The scan should be head,chest, abdomen in my opinion. Aggressive and different diagnotics procedures instead of the routine CT Scans can be extremely helpful in my opinion. I wish your sister the best and what ever is causing her pain subsides quickly.
God Bless,
Jeff G.