Had mirena fitted 1st July 2003, due to uncontrollably heavy periods, (felt as if I couldnt leave the house/toilet for 2 to 4 weeks every period!) I didnt think that the fitting hurt at all. It felt like having a smear test, only lasted a bit longer. I have had 2 children though and maybe this helped me relax. Come on, it cant possibly be more painful than labour can it?
Anyway my periods havent stopped yet since the fitting like some women say, but they are certainly more manageable. Havent really noticed any other side effects. Hope this posting helps and good luck with yours.