In fact, one breast cannot be twice as big as the other. But yes most of the married sisters face this problem but it is not a problem. Breasts are not a big problem. Give milk to the baby from both breasts. In most cases, give more suck to the small breast. Small breasts are not a big problem, it is normal if the breasts are healthy. Wear the right size bra for her , mix coconut oil and Vaseline on the big breasts and massage twice a day with one hand up and the other hand down. There may also be tumors in the breasts larger than normal , the breasts may swell , so be sure to consult a gynecologist to be sure. You can also press the big breast with your hands to see if there is any tumor and check if it hurts.