Flank pain, blood. Back pain in the flank at level of lower back ribcage, can be very severe kidney stones. Blood in the urine, in any amount, either bright red or rust brown. Flank pain with fever, chills 7 vomiting. Back pain aftr uti. Puffiness of the eyes or ankles. Thirst and producing excessive volumes of urine. Absent urine production from acute medical kidney disease. High blood pressure & headaches etc.