Hi! I used to have those every other month at some point of my life, and I still do occasionally. It was due to my hormonal imbalance. The first time I found that out was the regular ultrasound and since then I became scared and obsessed and started having ultrasounds every cycle and apparently every other cycle I had cysts. The doctor said they were functional, meaning they appear one cycle and go away the next one or the second one. They never really bothered me, though sometimes when they were too big I had a bit of pain during intimacy (just change the position). I know cysts can be scary but I guess it all depends on the type of the cysts and the vast majority of those are benign and resolve in a couple of months
I'll share mine. I had one at the time that I was trying to get pregnant. I had for a couple of cycles bad cramping at menstruation time. And then I had a period that was horribly heavy and I had excruciating cramps. Everything was amplified. It was not bad enough that I went to the ER or anything but bad enough that I mentioned it to my ob/gyn. Diagnosis? Passing a simple cyst.