I have the kind of IUD without hormones. It has only the copper wires around the tiny T shaped device. Mine was inserted during another procedure, as well, so I am unsure how much it hurts under "normal" circumstances. It apparently works for about 6 years, so I have a bit of time to go before it needs changing.
I have noticed strong orgasms can be a bit painful, but only a small percentage of the time. (A little pain doesn't bother me anyway, when I am having so much fun!

)