I had flank pain in November. I had a urinalysis done which showed blood in the urine, and an ultrasound, which came back normal. The pain went away after a few weeks. It started again in April. Again there was blood in my urine, and I had a CT scan and an ultrasound done. Both came back normal. The only difference was one of my kidneys shrunk by 2 cm since November. The pain is getting worse and my doctors advice is to take Tylenol. Should I get a 2nd opinion? Or see a specialist?