Uterus/ovaries twitching suddenly?

I have had the Mirena IUD for almost 2 years now and within the last 2-ish months, I’ve been experiencing weird twitching sensations in either my uterus or my ovaries. No suspected pregnancy and yes, I have taken a few tests to confirm. It seems to only happen on my left or right side at a time- never in the middle, which is why I suspect it may be my ovaries. It happens a few times a week but today I’ve been noticing it a few times per hour. Im currently on day 6 of my cycle, I still get “periods” regularly. The twitching is not painful at all. It is ever-so light. It feels like twitching/fluttering. If you have ever been pregnant before, the best way I can describe it is those flutters you feel when you feel their kicks for the first time. It lasts only about half a second. It has only been happening in the last few months. I’m not sure what could be causing it. I have a 22 month old. No other children. I’m not sure if this is caused by the IUD or if it could be something else?