I've been having low back and flank pain on my right side and my creatinine level is 16.9. is this kidney infection?

Unlikely: The creatinine level indicates significant kidney disease that would have to affect both kidneys (did you mean bun/cr ratio?). Infection usually affects only one or the other. If there is already underlying kidney problems, then infection could worsen things. Difficult to provide more insight without more information.

Labs: I am hoping your creatinine is 1.69 and not 16.9. Your labs can't answer the question of infection and pain. You have abnormal Kidney function either way and your pain needs a exam and suggest visit to the kidney doc. Please check your labs, 16 creatinine needs intervention. Suggest see a kidney doc .