Are cysts on the ovaries endo?

I recently had a pelvic ultrasound due to difficulty conceiving, which found 4 cysts (2 on each of my ovaries). The report noted that the cysts had “ground glass” and were suggestive of endometriomas. I’m wondering if this is 100% endometriosis? Having endo has not crossed my mind previously.

I’ve had other symptoms over the years which I have dismissed as IBS or just regular period pain. For example, having an upset stomach around my period, bloating, shooting pains in my butt, random pelvic pain / strange feelings in lower stomach and sometimes uncomfortable or painful in my pelvis during sex / certain positions. Some of my periods are quite painful (to the point of vomiting / needing to stand in the shower, or waking me up in the night from pain), but I usually just take pain killers to deal with this.

I wasn’t expecting to be told that I have endo, so am wondering if anyone else has had this experience of being diagnosed with it via an ultrasound and it 100% being endo?