I have left flank pain, sometimes comes around front below ribs and sometimes up back. history of gastritis & gerd. taking pantoprazole. had neg. ct scan 9mo ago. cbc, urinalysis, crp, bmp normal nov'21. my dr says it is back pain, i'm not so sure?

Your pain is not from gastritis or GERD and less likely from the left kidney with negative urinalysis and CT scan. Your doctor may be correct, pain is more likely from musculoskeletal source. Musculoskeletal pain is usually exacerbated with certain body movement or position and it is usually improved with local massage and heat pad. Therapeutic diagnosis with Celecoxib may be helpful.