What Causes Breast Pain Before A Menstrual Cycle?

my wife is 38 years old. maried in 1994. Ist child in1996 IInd in1999. both ceaserian. sterlised during IInd dilevery. from last few months getting pain in her both breast after a week or so of mc. after mc pain disappeares. again after about 10 days pain starts and continue till next mc. there is no any cist like thing in the breast. local gynoco digonosed as harmons problem and prescribed 3 months medicine 1. CRISANTA LS(drospirenone and ethinylestradiol) a pac 24 tab , taken from 5th day of mc. 2.PRIMOSA1000 PL . ADVICE