From what ive been told, its normal for cysts to form and rupture and go away on their own, these cysts are usually small and filled with a clear fluid. Cysts typically associated with endometriosis can start small but may get bigger in size and in my experience they are filled with blood they can be referred to as “chocolate cysts” because they show up in an ultrasound as dark or black sacks (as opposed to the clear fluid cysts that are grey or lighter i suppose)

So cysts doesnt automatically mean endo. Endo also usually comes with other symptoms especially pain in the pelvic area where the cyst is located.

Also if you want to schedule an ultrasound ive been told the best time to go is right after you finish your period like it produces the clearest images when you get a scan around that time as compared to getting one before or during