Breast pain and nipple pain are considered the following possibilities: firstly, if you have had sex without safety measures in recent times and your period is delayed by a week or so, it is considered to be caused by pregnancy, which generally increases in size and produces pain in the breasts and nipples in about forty pregnancies. Secondly, you may be suffering from breast enlargement, the typical symptoms of which are breast lumps and breast pain, especially before your menstrual period. Most women experience chest pain and nipple swelling before their menstrual period, which can be recovered after the period is over. The pain may also be caused by mastitis. Finally breast cancer or abortion or pubertal development may also cause this symptom. If the pain is more intense, it is better to go to the hospital for further examination.