You don't say how long ago you had surgery. I noticed that my bladder capacity seems smaller, so I go a little more often.
Having a catheter in for a week tends to mess up the normal workings and it takes a little time to get back to the way things are supposed to be. I was told to try to "hold it" a little longer each time to help rebuild the muscles.
I also had a lot of normal swelling in that area right after, so, in the beginning, it was difficult for me to tell when I had to go and when I didn't. Sometimes, I'd think I really had to go, but it turned out I was mistaken. It took a while for things to settle down and normal feelings and functions to restore themselves.