Cervix cramps???

So, I've been to my obgyn about this and they said everything looked good. My IUD is where it should be, the strings are the right length, basically clean bill of health. I've had the IUD for at least 7 or 8 months now and my period and cramps have practically gone away. EXCEPT I get these really bad pains throughout my lower abdomen and uterus, that travels down in to my cervix. It doesn't seem to come at any specific time.

I was just hoping that someone else might have experienced this.