I hope you don't mind me responding to this but let me set your mind at ease, (this is my area of expertise)
for procedures like this you will definitely have a pca where you can press a button for a bolus of medication and it will stop you overdosing but you can press it as much as you need, and you'll only be given a dose when appropriate Ie every 15 mins or so.
You might have an epidural/ spinal block for the first couple of days, definitely for the first day, you'll get a lot of local into the wound area so that will be numb for a long time.
I was unfortunate in that morphine makes me vomit copiously and I am a hideous patient who just wanted to go home so said I felt fine and then physio came and it all went wrong. I think I didn't get good pain relief because I told them I was fine until it was obvious I wasn't. I'm an anaesthetist and I work with half the people I've seen so they should have really just ignored me and cracked on, also my lung surgery was key hole (apart from the tumour removal) and a lot of drs think that keyhole = no pain but they've aggregated a nerve and that caused a lot of my pain.
However I can guarantee that you will be very dosed up on a lot of pain killers because its obviously a sensitive area, I've looked after patients (during and after surgery) who have your surgery and I made sure they had every single opportunity for pain relief in my control. Also don't be a martyr and not take anti sickness, there are lots of options and you don't need to be in pain. I was an idiot, don't be like me.
If you have any questions please dm me if you want to