Maybe nothing. Uterine fiborids are quite common, especially in african american women. Often they don't cause much problem, but some women may experience painful and heavy menstrual periods, causing anemia etc..Progestin only birth controls may help a bit. They can be surgically removed, selectively embolized (cut off blood supply), or hormone suppression. Consult your doc. Good luck.
Surgery. No medication permanently shrinks fibroid tumors. If you have symptoms options exist to help improve them: myomectomy (cutting out fibroids, repairing uterus) for women who desire future pregnancy hysterectomy (fibroid uterus removal), preferably laparoscopic or vaginal routes, best choice if family complete uterine artery embolization - injection of foam to block uterus blood supply.