Let me start by saying there are various types of pain. I've cracked my head open on a brick fireplace, I've had a finger hit with ammonia anhydrous spray and freeze almost instantly, freeze burn sucks worse than fire. I had my hand caught between a tractor tire and a 3 point cultivator and the pressure burst open a finger. I had a 1000 gallon water tank fall on my foot and lost a nail, I've had a completely ruptured disc in my back and needed a fusion.
I think I'd rather go through all of those again at the same time than ever experience a kidney stone again. The pain is indescribable and unlike other pain where you get brief moments of relief in waves, a kidney stone pain is always on and does not relent.
The second worst pain is peeing after you have it surgically removed. Nothing like pissing pure blood at the temperature of molten lava.
The third is having the stent removed, it's like a tiny thorny vine and the thorns are pointed towards the exit

Well if the nukes fly tonight I hope there's at least a few that refuse the orders