Hi and :welcome:
I am 7 days post-op and was open bypassed. Individuals' ability to deal with pain varies and I am in the tolerate high pain ability. But I felt pain after.
Make no bones about it, it is a major op, your insides have been re-plumbed and you will have a vertical scar from just under your breastbone to near your navel.
But! They will ensure you have pain relief, usually a morphine drip, which is self-administered via a button. Don't worry; you can't OD, it's on a timer!
Dissolvable paracetamol takes over after a couple of days and generally does the trick, but if you find you need something a little stronger, then do please let the hospital know before you are discharged. They will ensure you have the correct meds to take home.
You will most likely have pain from trapped wind too but that is par for the course and is sortable by moving regularly, sipping warm fluids and I find gently rocking back and forth helped me.
All the very best and keep talking.