Gallbladder. Christ, I'd rather have a baby any day. I managed for a few days on painkillers and a constant hot water bottle, but I remember letting the cat out and sitting on the sofa, and suddenly got a stabbing pain so sharp it made me cry. I've broken or cracked my ribs numerous times and like to think I have a high pain threshold, but that was something else. Went to hospital and was on morphine which barely touched the pain
More recently and stupidly I made my dinner far far too spicy using an additive that can only be bought online. Oddly, it didn't taste that hot going down, but about 15 mins later I was writhing around, sweating profusely, curled up in the bathroom wondering if I would be sick, stomach lining absolutely on fire. Never had anything like it. Even a week later I feel constantly low level nauseous, especially after eating, and I haven't touched spicy food since. It was entirely self induced though so I don't expect, or get, any sympathy from anyone 
As for your OP, I try and be a 'ride it out' kind of person, with whatever pain relief is to hand of course, but when you're in the thick of it and the worry that it'll get worse, it definitely isn't easy.