Your doctor will look at your pelvic organs, your uterus, ovaries and fallopian tubes. Endo can also be found on your bladder, rectum abdominal wall so he can remove those implants as well. There are both surgical and medical ways to get rid of endo. Basically you can have your endo treated by surgery or by medication. They can remove all of the implants surgically which is usually the best way.
Cysts are very common for many women.
I do have fibroids, too, but my period pain has been worse, and having a different pain. There is always that possibility if your ovaries are intact. If you have had your ovaries removed, then no it is highly unlikely that synthetic estrogen can stimulate endometrial growth. Embarrassed to say, but I have cramps and then go to bathroom pain as well. It just all depends on what they see and how well they can reach it.