Physical pain? I've had a spinal tap, countless perforated eardrums, dental nerve pain, broken bones and dislocated joints. You might consider me quite unfortunate and each of these is a story in itself. (The burst eardrum is definitely the worst of these, in severity and relentlessness) So anyway, I'm no stranger to physical pain.

BUT, I'm even more unlucky in that I suffered from a pretty rare condition called recurrent corneal erosion syndrome for three years after somebody poked me in the eye accidentally whilst he was trying to do the Saturday Night Fever move.
It's hard to describe the pain, but I'm told it's a contender for the most painful condition known to medical science. A woman once popped her own eye out with a spoon rather than continue to live with the condition. The cornea (layer of transparent tissue covering the pupil/iris) is pretty bad at repairing itself. Like the other tissues in your body, it attempts to bond with nearby tissue when it's ruptured. (Think on how a cut on your hand heals). Except with RCE, the cornea preferentially adheres to the eyelid instead of itself. So, when you sleep, the front of your eye "heals" onto the eyelid, and then it tears open when you next open your eyes. Each time you sleep, the wound gets worse, until you can no longer open or close your eyes without agonising pain. So you are utterly sleep deprived, unable to blink for fear of the worst pain you've ever experienced every single time you do, and it hurts a good amount constantly anyway. It's as good an example of your own body torturing you as you could ask for. And it goes on and on and on. There's only one treatment which works, which is a type of laser eye therapy, for which the expense is very high. So I had to wait 3 years. The only way I managed to continue functioning was when I was allowed anaesthetic eye drops, which became like the air in my lungs. I would have to beg for them regularly, and I never had enough. Every night and morning I had to remember to squirt gel into my eye before closing/opening it, which would stop the healing effect IF I was lucky. Had the laser therapy not worked I don't know what I would've done. It's been eight years now, but it's "recurrent", so there's no guarantee it's gone for good. I wear glasses that I don't strictly need now, to make sure my eye is at least partially protected at all times. Sometimes, especially if I've drunk alcohol and I'm dehydrated, I get a little reminder that it's there. I live in fear.