Wow some of you sound lucky from what you consider your "worst" pain. I have broken several bones, been electrocuted, fell 20 feet onto rocks, been attacked by a dog, tons of sports injuries, got hit the head with a bat, teeth removed, etc Lets just say I went through a lot.
But the worst would probably be when I was about 16. I was playing football on a cold fall evening. It was even raining, so the field was slick as well. I went up to the line, the Quarterback did his thing and as I went to make my move around the guy my right foot slipped underneath me. Now that wasn't too bad, but the a-hole that was guarding me decided it would be a good idea to push me backwards as I am down (even though I was completely out of the play by that point). Imagine your leg and foot shaped like the letter "L", and then imagine the bottom part flipping to the other side. Well the next few moments was probably the most tremendous pain I will ever feel for the rest of my life (hopefully). I was screaming my head off from the pain and the ******* was still pushing me backwards. At this point I black out. Eventually I come to again on the field. The assistant coach and trainer help me up and use themselves as my crutches. At this point I was completely out of it and apparently I said I was fine to walk on my own and I couldn't feel anything (the scary part is I remember not feeling anything of my right foot as if it wasn't there anymore) As I am typing this it is making me uncomfortable reliving it over again. Long story short I ended up going into surgery to repair my ankle. A separated and broken fibula, two screws, tendons all messed up, in a cast and walking cast for 6 months, a year of physio later and that was a hell of an experience.
It's doing fine now, but it aches a lot times. I am now squemish with anything involving the knees or ankles. I can't stand seeing a serious injury to the leg anymore despite having no problem seeing any other type of injury or even cadavers(dead bodies) etc on videos or medical books.