Was it a full hysterectomy? Like did they leave your ovaries in? I know sometimes ovarian cysts can cause blood in the urine.
I don't think that that sort of pressure from the binder could cause kidney issues, but it might aggravate existing ones. Having had a really kidney infection, I would recommend not binding until the pain is gone and you've had some time to heal, because pressure in that area does make it worse when the organs are actually inflamed and tender.
FWIW when I had my infection I didn't have any of the "typical" symptoms, no pain with urination, no frequency, I just got really sick to my stomach and my pee looked like milk.

Hope you get your results back soon and the mystery will be solved.