Get a 2nd opinion, especially if you haven't had children. Fibroids are common and are not usually resected unless there is a major problem. If they were found incidentally, they probably need no treatment. Fibroids are benign muscle tumors which occur in the uterine muscles. Some women are very prone to these and develop quite large growths.
Symptoms range from none to excessive pain and bleeding with ones period.
Occasionally, they will interfere with pregnancy although this is more controversial. They should not progress to cancer. Endometriosis is quite another problem. Endometriosis represents some of the cells from the lining of the uterus migrating out the fallopian tubes into the abdominal cavity. Here they attach to different structure and continue to slowly grow and to act like endometrial cells from whence they came.