What Causes Pain After Being On Microgynon?

hei it about 5 mounts now i'm taking microgynon. i'm ok with my menstruation, but i fell so much pain in my breast and my breast a bit bigger than before. such pain i do normally fell it a week before my menstruation come and a soon i get my menstruation i don't fell anthing until the next menstruation. but since with microgynon the pain is continous.
what should do?
thanks