It didn't hurt her at all while she had it... you could give it a good old poke and she didn't bother, but it had to go because of the size - eventually it would have prevented her eating. It was a few years back and I can't remember properly what it was but I think some sort of cyst. What I do remember was they said they couldn't stitch the wound or it would reform so she had to come home with a big gaping hole in her neck which looked pretty horrifying! The wound had to be syringed-washed very regularly with hibiscrub, and she was kept on painkiller and antibiotic, but to give her credit she was very stoic and didn't fuss at all. And didn't stop eating, I don't think she lost any weight! It took about two weeks to heal up and we were very proud of ourselves... although when you go back for the post-op check and the vet looks surprised that she's not only alive but on the mend it does make you wonder what they thought her chances actually were!