I had the surgery in my teens - I was probably 16 or 17 at the time. Here was my experience:
It didn't involve any external cutting; everything was done through the nostrils. I was awake the whole time, on local anesthesia. I didn't feel any pain during the procedure, but it was uncomfortable feeling the doctor tapping inside my nose, basically chiseling the bone. It did start to hurt a little from time to time, I would just say "ow" and they'd give me more anesthesia. Actually, I felt surprisingly cheerful through it; found out later they'd used cocaine as part of the pain killer.
It hurt a LOT in recovery, though. I was on a pretty heavy codeine prescription that mostly just took the edge off. I had a pair of three- or four-inch long splints up my nostrils, back up my sinuses, and lots of packing and ice. I think it was a couple of weeks before all that came out, if I remember right. If you drive for a living, you won't be able to work with all the codeine.
I still have lots of trouble breathing through my nose and probably also a sleep apnea (supposed to get that tested soon). The surgery improved it a little but didn't solve it totally. I'm not sure how much of my breathing trouble is because the surgery didn't work or how much is because I'm allergic to half the planet and my passages just swell up anyway, regardless of any blockage from my bone structure.