I have had mulitple UTIs in the past year. About three months ago, I had a kidney infection . Five days ago, my kidney was aching (not the pain like I had for a kidney infection), I have been nauseous, and very tired. My urine culture came back okay. I got a KUB test done today. Of course, I viewed the CD and the one kidney shows black spots all over it, but the other kidney does not have that. What could that possibly be?