Mirana cysts

So I got the progesterone iud last month and yesterday I went for a ultrasound to make sure it was where it’s supposed to be. Well it was but they said I have a cysts on my left ovary it’s measuring at 4cm I’ve never had anything like that EVER! And I’ve been very lucky and able to convince my children very fast.....idk what to do my gut feeling is to remove it my doctors on the other hand think they will go away but some might show up again....and now today I’m having pain on my left ovary! I’m just so afraid something might happen and I won’t be able to have more kids...