My nieces have endo on both sides of their family and I will tell you-- If they so much as GRIMACE when they get their first period I will be taking to see the doc that did my excision. I can't imagine how different my life would be if I hadn't suffered for 23 years. Get a GOOD doctor. Get a REAL surgery.
(I had 1 not good surgery. It was useless. Do your research)

I am only 18 and going for my first lap next week, I had an external and vaginal ultrasound both came back normal but my gyn told me those aren't the best tools for diagnosing endo, that the only way to know for sure is a laparoscopy because it is so different in everyone, and the can remove a lot of it during a lap. I would push a lap with your doctor and if they won't help you, maybe find a new one.

Have you ever had a laparoscopy done since your diagnosis at 14? You more than likely need the spots excised and cleaned out and then start taking hormones to keep everything suppressed. That's what I've done in the past with great success.

I had my first Laparoscopy at 17 but similarly to you it is thought that I have had it since I was 13/14, I think you should probably get a second opinion from a different Gyney because the first lap gave me massive relief for months after.

I had a lap to remove endo at 15 17 and 19 then a lot more to follow.. But I had those 3 in my teens. If birth control isn't helping your symptoms I would say you are a candidate for surgery you will recover quick. Maybe try a different doctor or tell the doctor of your concerns. I have however been told too young for hysterectomy.