IUD insertion

So, a few weeks ago I went to get an IUD and the proses of putting it in was so painful that I had to ask them to stop. I typically have a pretty high tollerance for pain, and I was wondering if anyone else has experienced the process being so painful?? I have friends with IUDs who said it was a super easy and hardly painful experience. 
Also, I ended up getting the pill and since taking the pill I've been extremely constipated and randomly cramp for a few seconds throughout the day. I have pretty tender breasts too. Has anyone on the IUD experienced symptoms like what the pill is doing to me?