Why does this happen at "that time of the month"?

why when i am going to get my period my breasts really hurt?
and why does it still happen when i am on the pill? i thought my body wouldn;t know i would be getting my period soon.Why does this happen at "that time of the month"?
its hormones it happens to everyone
that is just a part of PMS. Mine do the same thing,
It is natural and count yourself lucky that only your breasts hurt others have very upseting abdominal pains too. The pill does not help you to stop with periods but it helps you to have a normal cycle and prevent you from having unplanned pregnancy. Don't stress a lot about it as it is only for a few days. Soon you will no longer feel the pain. Girls go through that time and it pass.