Why are my breast getting bigger i am 51 years of age?

Hormone changes: As women come nearer to menopause, there is an imbalance between estrogen and Progesterone production from the ovary, with estrogen being dominant. Estrogen effects on the breast can include breast tenderness and enlargement of the breast. A mammogram is indicated (my opinion) after the age of 50 which may help dissipate any cancer concerns.