I'm also menopausal, thought my female organs were retired and dormant. Then I found out I had a large (10 cm) cyst on my left ovary. Just had it removed a couple weeks ago.
Considering you're having pain and have a history of BRCA, please get in to see a gyno. It would be a good idea to ask for a trans-vaginal ultrasound too. I know, who would want that? But that's the best way to see what's happening with your ovary. A manual exam may not be enough. Please don't wait.
I had the exact same thing and I , too, am post menopausal. It really felt like Diverticulitis which I had awhile back , but when I went for my annual , my Gyno wanted to rule out anything ovarian. Evidently the left ovary is right next to the descending colon.
Well, in any case, they found a very small cyst (which turned out to be benign) 2 fibroids which are supposed to disappear with menopause and some fluid in the uterus. Had the C&D, removal of ovary (because at my age, who needs that right?). Actually the Dr. told me that the pain probably was not related to the cysts as they really were tiny.
However, I totally agree with Ireneo; have it checked via transvaginal . My Gyno also ordered a CA125 blood test after seeing the cysts. I understand that test is not absolutely accurate, but at our age, I've heard it's not quite as "inaccurate" . Always better to be safe.. good luck