Shots

I received a couple of injections today and was thinking: what is easier – to give shots to yourself or to other people. I have to give shots to myself once in awhile and it was hard to break the psychological barrier at first (I knew it wouldn’t hurt and it was still hard, I just love myself too much), but I can’t even think how hard for me would be to do it to someone else. When I was young and a Soviet dentist performed a root canal on me without anesthetic I found out what the real pain is (waterboarding is for pussies) but I couldn’t be in place of that dentist.
So how does one breaks through fear of causing pain to another person.?
P.S.This is a different situation from punching someone in the nose. This I a don’t have a problem with.