I had a cap for my tooth poorly made, and basically, food got under it. Bacteria basically ate the tooth away. Then, the pain started. Imagine having a soldering iron plunged into your ear. FUCKING HELL. I could not sleep, think, eat, breathe, or anything without crying when it hit. It'd happen randomly, even during class, or half-way through the night. Took a month for the doctor to see me. Then it just kept happening before the operation happened to remove the cap. I was given anesthesia for it, so I can't really remember. Now, I don't usually cry from pain. This was so intense that I could do nothing else.
Another was an infected ingrown toenail. Hurt like a ***** for a week. If I moved it, pain. Then, of course, I hit it against a table leg...
I went to the doctor as soon as I could. The "operation" took 5 minutes, no anesthesia. Just pain. I couldn't see what had happened, as he put some curtain thing between me and my toe, so that was good, at least. Hurt even after the op. For 5 minutes. Just remained the same, and then disappeared.
EDIT: Toenail, all my fault. Kids, don't bite or pull your nails. Finger, toe, whatever. I did, for about 17 years. I'm 17. At least once a year, I'd have to get an operation for something stupid that I caused. I did stop, but that took a hell of a lot of willpower.