Why am i getting lower back pain, im getting a cat scan for a sinus infection and now this, did the infection spread to my kidneys,i have to get tested at urgent care so im thinking of asking them to check that out while im there, have kidney issues?

Low back pain: It would be most unusual for a sinus infection to spread to the kidneys. Unlike bladder infections, kidney infection(pyelonephritis) is a serious infection causing midback and flank pain, fever.and chills. Low back pain is common & is usually from osteoarthritis,osteoporosis, degenerative disk disease or lumbar muscle strain. Have it checked at the clinic.