Days leading up the my period i start getting pain in my right side of my stomach. and days after that i still have pain. is it my appendix?

Endometriosis?: Pelvic or low abdominal pain with menstruation is typical for a endometriosis, in which tissue from the lining of the uterus implants in the abdominal/pelvic cavity. The implants swell and bleed with hormone fluctuations, just as the uterine lining does, causing pain. Once in a while appendicitis can come and go, but would not be timed with your periods. See a gynecologist. Good luck!

Period pain: This is not your appendix. A more likely possibility is endometriosis which causes pain around the time of menstruation.