I had a catheter during surgery, but they removed it before I was awake. My hospital got me up pretty quickly after I came to, so I would just use the restroom. This may vary depending on this like the type of surgery, the hospital, your age, mobility, etc. I am 34, had RNY, and no mobility issues going into surgery... so they got me out of bed pretty quickly.
I’m a nerd and read through my surgical notes. General anesthesia does not numb your stomach. However, they did inject local anesthetic near each incision site at the end of the surgery. Post surgery you will be on some sort of pain medication.
My incisions never hurt. My abdominal muscles did, though. I would describe it as quite a bit of soreness the first few days, but it is tolerable and there are pain medications if it isn’t tolerable to you.