I get bad right flank pain with my period why is that? can it be my kidney?

Maybe?: Flank pain can be indicative of a urinary tract infection, however, the fact that it comes with your period tells us that it could be otherwise since your kidney should be affected by your period. The presence of ovarian cysts however can also cause flank pain ethic could be worse on your period. Discuss with your doctor and good luck!

Related to menses: If you are having right flank pain with your period this could indicate ovarian enlargement involving a cyst versus endometriosis. Flank pain is associated with urinary tract infections and kidney stones but the pain would not come and go with menstruation.

It is referred pain: Sometimes during the period the uterus is irritated and the brain interprets it as flank pain. It probably is not your kidney but referred pain. If the pain increases with pushing on the flank area see a provider. If the pain increases in nature see a provider. With your MRIs being normal it probably is referral pain ask your provider for a medication to reduce inflammation.