I suffered with constipation for many years, along with vomiting and my doctor I was seeing at the time--kept telling me to do the fiber supplements, watch what I eat, etc. I just couldn't win. I had a hard time telling if I was having pain from endo or gastric pains. Over six years later I come to find that my gallbladder is barely functioning and had tons of scar tissue on it. Since having it removed I have dealt with constipation a lot better. But I also dealt with anal fissures and internal and external hemorrhoids. Keep in mind that everyone is different. I am only mentioning this to you because through extensive research I have found many endo patients suffer with gastric issues as well. So, please keep your options open. It never hurts to ask your doctor if it could possibly be your gallbladder causing these bouts of uncomfortability and constipation. I also had horrible pain on my right side toward my lower back. It was more up towards the rib area. The testing I had for it was called Hida Scan and it shows how much your gallbladder is retracting when given certain solutions in an iv.
I really hope you find something to help. Because constipation, along with what you already deal with is just so miserable. Best of luck to you! 💕