I myself have not been subjected nor fallen victim to any tremendous physical pain as I can recall.. So I'll have to say my emotional pain is the worst in my life.
A few years back, a friend (However, I didn't know him too well >.<) died when he and some other were out swimming, he slid on a slippery rock and hit his head severely, and fell into the water, he was found a couple of hours later by divers, as he went far down... Later it was discovered the hit to his head had been the death blow, which is at least was instant, and not painful.
My paternal grandparents both died this year, first my grandmother in late January, and after giving up without her around, my grandfather died in late June.
As I've long moved past these events, and coping with a depression about a year ago, my current pain is (as I've mentioned in appropriate threads around here already) being in love for the first time.. I'll mention that I've never been with someone, I've never been looking for someone, and I've never felt the desire to be with someone, before recently, that is.
The fact that I admire this girl so much, and there is nothing more I'd want to than to make her happy, makes my heart twist, and as pleasant as that feeling is, I can say it hurts as well.. and, lame as I am, it hurts alot, as I believe she would have no real interest in someone like me, and thus she is the only one that could make the pain go away, so to speak. ^^;