i had a small one on my thigh, they are 100% painless. my doc removed it but i needed 4 stiches. that guys was huge, probably needed a few internal and external stitches. and the shit that comes out smells BAD.
Not sure they're always painless...i had a friend that had one in his back (had it removed surgically after) and he said it was agony to put pressure on it and the infection kept making it ill. His must have been pretty bad as he was on antibiotics for weeks and it still kept coming back. He had to go back to hospital every day to get it checked.
Btw, for the people who like gory things I saw a much worse version of this on youtube where they end up pulling it all out with a spoon and without anaesthetic. and that one is SICK.