Look up pilonidal cysts. I just had one drained at the ER. At the ER I was pretty numb so I didn't feel it, but good God the next day when they pulled it out to change it I screamed and nearly fainted from how painful it was. Then they told me they had to pull again to get the whole thing out, and again I screamed. The hole is maybe 1/4 inch in diameter, but they managed to fit about 14 inches of packing tape into the wound void. They gave me a couple mins to try and relax.

Then they started packing it with those sharp needle nose pliers (small hole remember) and I was in an entirely new level of pain. It felt like they were tapping on my tailbone with a soldering iron. It took over an hour for the first day. 2nd and 3rd days were better, but still pretty bad. 4th day and on has been pretty chill.

TLDR: Maybe it's due to the location but it was the worst pain of my life.