Hi,
Welcome to the ehealthforum and I am glad to help you out. Endometriosis can occur at multiple sites and give rise to various symptoms depending upon the location of the endometriosis.
If it involves the ligaments of the pelvic region, it can give rise to the low back pain and surgical removal of the uterus is not the answer to the problem and thus I would suggest consulting another gynecologist for the same and getting a laparoscopy done to look for the possibility of the presence of endometriosis at other sites causing these pains.
You might need a CT scan or an MRI also for the same. Meanwhile, the use of NSAIDS (painkillers) and drugs to suppress the ovarian function like danazol can help in mitigating the symptoms. I sincerely hope that helps. Take care.