Would kidney infection pain come and go or be persistent ? negative dipstick but flank pain

Pyelonephritis: If had a true kidney infection, also called pyelonephritis, kidney pain can persist for a few days to a week after the infection has cleared but should continue to improve. If it is persistent after a week, worsens rapidly, you see blood in your urine, or return of infection symptoms like fever, please see your local doctor for additional testing. Hope this helps