There are several possible reasons for the delay in menstruation for a week and the painful swelling of the breasts. First of all, the main manifestation of intrauterine pregnancy is menorrhagia, delayed menstruation, and possible swelling and pain in the breasts as well as hyperpigmentation and darkening around the areola. Secondly, ectopic pregnancy also presents with menorrhagia and possibly breast tenderness. Lastly, PMS is a condition in which irregular and delayed menstruation occurs for specific reasons, but there is no pregnancy. PMS may appear just before the menstrual period is due, and may include chest pain and lower abdominal cramping and pain. In addition, it may also manifest as mental symptoms such as lack of energy, and these are common causes.