What could cause nipples swollen and tender, breast feeling heavy and full and viens in breast, ?

HCG vs Prolactin. A few possibilities: 1) pregnancy 2) elevated prolactin which is the hormone that induces lactation 3) premenstrual for 1, get a pregnancy test for home use in your pharmacy, 2 your physician can test for this hormone, particularly if you have a discharge or milk coming out of your nipples, and 3 if you are in the last week before your menses.