A friend of mine has a lot of similar symptoms and she has endo. Abut 3 years ago they found a small amount and removed it and since then her symptoms have been getting worse. She has severe bloating most of the time, heavy and painful periods and she also gets the stabbing pains in the butt. A few weeks ago she got in the car to leave work and when she sat down the pain was excruciating (like a pointy metal pole!) and she cried all the way home.
Just recently she was at a wedding and a close family friend was there. He is a gynaecologist (or something like that) and he didn't have much advice. It was pretty much it is what it is
Sorry you are going through this, I always feel for her when she is bloated and in pain.