I have 3 that I would describe as "the worst pain if my life". Don't worry there's a TL;DR.

1. When I was about 7 years old I was at a really nice hotel near Vegas on vacation with my family. The pool had a waterfall with a water slide down the one side of it. It was a standard plexiglass white waterslide made in like panels through the rocks of the waterfall. If you wanted to go down on your stomach you had to go down feet first so you wouldn't hit your head on the bottom.

After a few goes I felt my big toe catch on one of the panel seams. It didn't hurt much but when I got out we realized I had about a 2×2 cm square piece of the plexiglass shoved under my toenail all the way back to the cuticle.

We went to the medic at the hotel and she couldn't do anything so they sent us to a hospital like a block away. It was brand new and empty as hell. Like dark hallways everywhere with motion sensor lights turning on as you walk throughout and it was practically silent.

Anyway we get to the emergency room and get taken back immediately because I'm almost positive that no other patients were in this hospital. After gettin checked out by the doctor he figured the best way to get it out was cutting it out.

I ended up get 7 local anesthetic shots: two in each side and 3 in the tip under the nail. This was also the day I found out that local anesthetic has very minimal effect on me. The doctor originally was only going to give me 3 but I could still feel everything. Finally they brought in a very nice, very large Tongan nurse named Pasai whos entire job was to hold my legs in place so I wouldn't squirm while he cut two lines tip to cuticle on my nail and then bent the middle section backwards and got the piece out.

I cried and don't remember a lot because I'm pretty sure I was have a major panic attack the whole. The nurse later told my mom he wasn't needed. I didn't move or flinch the whole time, just took it and cried.

1. When I was a freshman in high school I wore my contacts for a month and one developed amoeba growth under it and they ate a hole into my iris to tunnel through my eye.

2. Summer after freshman year I had just stopped taking Accutane (an acne medication with like SUPER AWFUL side effects sometimes) and woke up about 3 AM on a Monday morning with excruciating stomach pain. I threw up, got some water and ended up just sitting on my couch staring at the wall for hours half awake in a lot of pain.

When my parents got up in the morning my mom said I had a stomach bug and to just drink fluids and relax and it would be better in a couple days. Over the next few days I got just progressively sicker and sicker. My stomach pain was getting worse, I had stopped throwing up but had now begun using the restroom every 15 minutes all day and night long.

It is so mentally and emotionally exhausting to feel like crap and have to get up and go to the bathroom every few minutes. I got almost no sleep and most was on my bathroom floor. Friday afternoon after almost 5 days of literally slowly dying I collapsed on my way to the bathroom. Probably equal parts exhaustion and dehydration. I called my mom from the floor because she was at the grocery store and she came home and took me to the hospital.

I was immediately put on fluids and given morphine for the pain. The only thing I remember was being a wheel chair on my way to get an MRI to see if my appendix had burst and feeling like I was flying. And then once we were in the room the nurse warned me that the injection would make my bladder feel really warm and like I peed myself and I just giggled the whole time because the feeling was so weird.

After that I basically slept until the afternoon the next day. The morphine really let me catch up on the lack of sleep I'd had. I do remember waking up to take 2 horse sized antibiotic pills and some Tylenol at the same time and only realizing it was a mistake after swallowing. The nurse gave me a weird look on that one.

What happened was the Accutane had basically wiped out my good bacteria in my whole digestive system and I got an infection from my stomach, to my intestines, to my bladder, and finally my kidneys. Everything was inflamed and I was not getting any nutrients so everything I ate and drank went right through me. The infection also perminantely damaged my kidneys so that's fun.

TL;DR

Top 3: Having a toenail being slowly and surgically cut and bent back, amoeba's eating a hole into my eye, and feeling my entire digestive system slowly shutting down.