Kidney cancer?

I went to the Cancer Dr for my check-up after just celebrating my five year anniversary cancer free with Triple Negative BC. 2 monthes ago when my general Dr. found blood in my urine after a routine test he put me on antibiotics although I had no symtoms of a UTI. After 2 courses of antibiotics the blood was still there and he ordered an ultrasound. Well, 2 monthes later the Cancer Dr informs me that there is a sizeable mass in my left kidney and  a stripe on the kidney wall? It was discovered over two monthes ago! My GM never called! The radiologist strongly recommended a Cat Scan at the time. I was dumb founded and speechless not to mention shocked. My CT is scheduled for next Thursday but I am trying to move it up. Has anyone out there had this experience or a similar one? I have heard that some woman get these benign masses after chemo. I would greatly appreciate anyone who can respond. I am freaking out a little. Could this be cancer again in my kidney? How do they test it?