Most pain I have been in including carbon monoxide poisoning, childbirth,broken bones, gum praphing with no pain pills, fingers smashed in doors blisters etc was when my daughter tipped a highchair over and caught my big toenail on it and it fipped completely off instantly. I almost passed out and dropped her. There is no pain like that.
(years later) poked in the eye with a backscratcher?
actually the most painfull thing I every experienced was a burn to my arm from an exploding raidiator, and the glycol got into it and burned and burned and burned...well, you get the idea.