I have. When I had it, my gyn felt it upon exam. She told me the vast majority of the time, they are nothing, and told me she thought mine was nothing. She did, however, send me for an ultrasound, just being cautious. Mine was painful for quite a few weeks, maybe even over a month. Funny, too, because by the time I had the u.s., the original one was gone and I had one on the opposite side, from which I felt no pain. If you have the Mirena IUD, which I have, you're more likely to get them.
Hope your pain goes away soon.