I have lwr rt quad pn in abdomen and rt back flank. my back hurts most when laying down. i have a ct in 3 days. fam hst of colon cancer dad & brot?

Many possibilities.: Right lower quadrant pain with radiation to the flank can be many different things. Possibilities include appendix inflammation, constipation, kidney infection, kidney tumor, colon tumor, etc. The imaging study will be very helpful. If the imaging study is inconclusive consider having a colonoscopy to be complete. Good luck.

Needs workup: I'm not sure anyone can give you a good answer with the limited information. However, if the pain increases, and you develop fevers and chills or nausea, you should see a physician immediately. Diagnosis could be (among others) kidney stone, appendicitis, constipation, gallbladder disease.