When I had my first IUD I was totally unprepared for the pain, the doctor had told me it would be similar to a smear - yes if you're having a smear with a red hot poker. The only pain issue I have with my IUD is that the ovulation pains I've always had from got a little worse afterwards, most recent studies show that the Mirena coil is even more effective than the pill in preventing pregnancy (as long as you make sure to check your strings, a coil can fall out especially recently after insertion) and there are none of the worries about taking the pill. 70% of women who use the Mirena coil will stop having periods so that's a welcome benefit too.