Change in bowel habits and lower butt pain. Could that be old endometriosis?

Could be. Bowel changes and butt pain could be endometriosis if that's where your symptoms were before. You should make sure it's not something wrong with your colon though.
Maybe not likely. ? Defn of lower butt pain. Bowel habit change is seen with endometriosis but is usually a chronic and not acute change. It is variable in its occurrence even in patients with extensive colon endometriosis. To have buttocks pain with endo would imply that there is sacral nerve involvement. I've seen it but it is rare. Hope that helps.