If your period is delayed for three days and your breasts are swollen and painful, you can’t rule out the possibility of pregnancy if you have had sex without taking contraception. It may be endocrine disorders caused by delayed menstruation, it is best to go to the hospital in a timely manner to draw blood to check the blood HCG, you can determine whether or not the pregnancy, if you are sure that the pregnancy do not have to worry about, the breast pain in the third trimester of pregnancy can be disappeared. If you are pregnant, you don’t need to worry. Breast tenderness can disappear in the third month of pregnancy, so you should pay attention to getting enough sleep, strengthening your diet and nutrition, and supplementing with folic acid to prevent fetal deformities, as well as regular ultrasound checkups. If you exclude pregnancy, consider endocrine disorders caused by the best check hormone six, it is best to use reasonable medication, usually pay attention to breast local massage and local hot compresses, can improve the pain, can ultrasound examination of the breast, to exclude the breast hyperplasia.