Out of every single injury i've ever had (and there have been a few) no pain has ever come close to standing on a UK 3 prong plug socket bare foot....

One of two things.. appendicitis.. that stuff hurts.. or my infected nailbed on a finger.. let me explain it this way.. once we managed to open it up and get most of the pus/gunk out.. and i put it in severely boiling water to sterilize it.. the pain from the finger hurt more then the boiling water.. the water actually SOOTHED it... crazy.

For a week I had random colon spasms, causing my stomach to feel like someone was shoving a hot poker into my stomach.

Had about 30 shots of local anaesthetic in my back once... It still didn't mask the pain of having a 3 inch needle directed through my coccyx and having a shit load of steroids pumped into the tiny gap where the main leg nerve is...

If you've ever experienced nerve pain you'll know how I might have felt whilst having this done.... For those that don't, imagine having a knife cut down your entire leg and then filling the slit with boiling water...

I've broken numerous bones and dislocated joints. Its a toss up between dislocated shoulder, dislocated knee cap and breaking my fibula. My fibula was when I was only 8 so the pain may be exaggerated by my young age.

The shoulder and knee cap were both equally excruciating, I really can't pick between them. Maybe leaning to the knee cap, simply the sight of it completely out of place made the pain that much worse.

Black Arrow Officer:
Cluster headaches. Fuck those to the pits that are deeper than the deepest pits of hell. I literally felt like I was being stabbed thousands of times at once, while having salt poured all over me. I think the picture on wikipedia sums those up real nicely:

I used to get those a lot last year. Was damn near clawing my eyes out before I went to a doctor.

Currently got 2 ingrown toenails, one on each foot. So yeah, ouch.

Also, I've never been stung by one, but these make me want to stay out of the marine when I go to Brisbane:
http://en.wikipedia.org/wiki/Irukandji_jellyfish#Irukandji_syndrome

When i broke my arm (i fell off my bike), both of the bones in my left arm were snapped right in half. I never cried.... it hurt too much to cry.

I had to deal with a toothache brought on by a tooth that needed root canal surgery.

Essentially what the problem was was that I had an exposed nerve and an abscess in the tooth, the abscess itself is bad enough since it pushes down upon the nerve causing pain but the addition of the exposed nerve meant even simple things like eating or drinking or even breathing through my mouth became a test of my tolerance for pain.

Imagine a regular tooth ache and magnify it by 10 or 15, then imagine that pain unceasingly for over three months; i'm sure that in itself it is not the worst pain in the world but because of the constant inescapable nature of it it becomes one of the most excruciating, sanity destroying pains you're ever likely to experience.[1]

I mean, because it never stopped I even found it hard to sleep and the only way to deaden the pain enough to bring sleep was to (carefully) lance the abscess and then to wash the tooth out with some very strong vodka but even then within an hour the pain would return in it's full fury and wake me up again so the exhaustion caused it to be magnified yet more; towards the end even the lance & vodka trick stopped working so the only times i'd ever really sleep was due to passing out from exhaustion.

People seem to say that root canal operations hurt but to be honest in my experience as soon as they stuck the anesthetic in me I felt like I was in heaven.

And you can bet your ass I brush my teeth twice daily now.

Accidentally tearing open a section of my circumcision wound.

Probably a tie between stamping on a pin/nail that went a couple of centimetres into my foot, and falling onto a wall & grazing my shin whilst running. The last one was probably worse just because the wound had all sorts of gravel in & needed disinfecting, and I had to run a couple of miles before I could get to hospital.

It would have to be when my knee and ankle dislocated and relocated themselves in the space of two minutes. Basically, I had roughly 1500 pounds of large, sweaty men fall on my leg when it was bent at a weird angle, causing those two joints to dislocate, only to have them right themselves when I tried to move them. The trainer for the football team I was on told me that he had never seen it happen, but that both joints were dislocate.

edit

Suffering an Unhappy triad injury during a football game my freshman year, the pain was so unbearable i went into hallucinations until the ambulance got there.

I have a high pain threshold so stuff doesn't hurt as much as it should. I'm searching through the old memory bank and nothing uber painful comes to mind. I get the odd bout of toothache in a tooth that's missing a half, but that's more annoying than painful. One time at rugby I fell awkwardly on my ankle that hurt a bit but it wasn't like having a pike through the head. I couldn't put any weight on it the fucker just gave way, I hobbled all the way home it took 20 minutes longer than it should have. Completely fine the next morning. Wait once when I was 10 I had an inflamed ear canal that fucking hurt.

usmarine4160:
Got my nipples pierced :)

That's pretty quick though. Also, why is pain measured in size OP?

IDK, it's a toss up. I had a spinal tap when I was 5, but I don't really remember that. When I was 13 or so my doc botched an ear cleaning. Wound up with a lot of water stuck behind my ear drum. By the end of the night it was unbearable and I was in the ER getting some percoset and a referral to an ENT. More painful than the time my foot got stuck under an elevator door.

Was hit by a car,my leg was broken in half; I could kick my knee if I were concious long enough after.
But that doesn't count I guess because I don't remember it.....

I guess the surgery I had about a year later to have the metal bar in my leg taken out; my leg swelled up to 3 times it's size and was all purple and yellow...so much more painful than any pain I experienced after the initial break >...>

I had to have all the teeth in my upper jaw removed and replaced immediately with a denture ontop of the wounds.

The drugs knocked me out for the best part of two days.. then I woke up a screaming drooling mess. I then had to remove the plate to clean the wounds and then put it back in around the swelling.

Ow.

Having my wrist bone pop out of my skin when I fell off my bike as a child. Fucking ow.

I broke both the bones in my arm and they started to overlap each other. My mom drove to clinic where for medical reason the Doc could not put me under while he set my arm. Pretty bad shit right there.

Continuing the ingrown toenail trend.

I had the whole ingrown toenail thong on both feet on the big toe, after having them cut out the doctor had to cauterize some of the wounds, all was well until we remembered our town has a massive senior community so getting my pain meds took 3 hours, the anesthetic they gave me at the doctors was starting to wear off as soon as i left the building....

Sharp pains in the urethra and rectum a few times last year whenever I had to go to the toilet at night. Worst part was that I constantly needed to pee for some reason, so the pain was fairly continuous and depriving me of sleep. I probably should've seen a doctor about it but I never did.
And one time I accidentally put some 92 degrees Celsius hot water in my mouth.

When I was younger, I managed to entirely rip off the skin and a great deal of flesh from the bottom of my foot. Having like, half in an instant hurt pretty bad, but it's all normal again.

I just remember massive amounts of sharp pain.

Foot cramps are a painful bitch. Aside from that the only thing I can think of might be falling down the stairs and skinning most of my left shin, but that was forever ago so I don't remember it that well.

When I had my ear sewn back together (really stupid accident) at the hospital. The doctor said that if he gave me anaesthetic I'd feel more pain. So I had to sit there fully aware for the whole time - approximately 100 years plus or minus a decade. Also, I was either 8 or 9 at the time. In the weeks following, I couldn't ever touch my ear for the enormous pain it brought me.