Hm...
In recent memory, grumbling appendix, probably. It was hell, I thought it was just a strange pain and it'd go away but it just kept getting worse and worse. Hit first at like 1am and I stayed up until like 8am when I could get to a doctor. It wasn't as bad as it could have been of course. It could have actually required surgery or popped >_>
I dimly remember splitting my scalp open by falling headfirst onto a concrete block while trying to flip over a horizontal bar at the age of three. It's really, really faded though.
The most painful thing that ever happened to me was probably before I remember, though. Before the age of 1 I pulled a kettle of freshly boiled water over me and lost most of my skin. I'm lucky to be alive - and even luckier that I've only got three smallish scars for it, one big one on my shoulder, one small one on my chest and a small plasma-drip scar on the back of my hand where I tried to pull the drip out
