The autonomic denervation view applies to chronic pelvic pain with, or without, endometriosis in the pelvis.
Ectopic endometrium can be found in the lower genital tract at sites of tissue injury e.g. in an episiotomy scar, at the cervix, or in a Caesarean section scar. These sites result from direct implantation at a tissue injury. Sometimes it is found on the surface of the diaphragm, this may occur in bulimia where vomitting causes injuries to the abdominal surface of the diaphragm.
Ectopic endometrium also occurs in lungs, liver and distant organs. Sites of broken bones may also attract ectopic endometrium. Blood-borne spread seems the likely means of transfer. In the autonomic denervation view endometrium attaches to a remote tissue injury though there is little primary evidence to support this hypothesis.
There is a useful and well-referenced summary here.