The mirena hurt a little bit when they inserted it....but its done really fast
When mine was taken out i didnt feel a thing. But i do want to add that the day after i had the mirena inserted i started having panic attacks. Apparently it triggers depression in one out of 100 people. So i ended up getting it removed for those reasons. It was a trigger in my mental health problems.
But it is an excellent form of contraception. I wish i could have used it.