Weight gain after surgery, help!?

I had my tubal ligation done nearly two months ago. I was 167lbs, (5'9/10) and losing weight beforehand.

A month after my surgery I gained 20 pounds.

I'm now at 195lbs and starving, eating the same as at 167lbs, working out the same (which wasn't much, I own two businesses and am busy!)...

Did anyone else experience something similar? Anyone have any suggestions?

My doctors told me "oh yeah pain pills will make you gain weight" flippantly. No explanation other than that.