When I was in the hospital for my Da Vinci surgery, my roomate had been there for a couple of days due to an infection after his biopsy. I wasn't able to communicate with him very well, since he was originally from a foreign country and it was hard to understand him. Plus, I had just come out from my surgery. He had done his biopsy in a different facility on a Monday, and was hospitalized by Wednesday. He wasn't very happy, and was trying to get some answers. Since they go through the rectum, there are possibilities for infections. If you still ache, I'm sure they have checked out other things, like blood in the urine or bowel movements or ejaculate. All that should be cleared up by now. Have you talked to the doctor doing your surgery? He needs to know if something is not quite right.
Good luck.