Sore breasts after a period can result from a variety of factors. Although it normally ceases during periods, there are also instances when it can be worsened because of too much ingestion of certain foods and taking some drugs. Caffeine and methylxanthine derivatives are popular food components known for their vasodilating action. As a result, the blood vessels servicing the breasts dilate and cause distention and pain. Salty food products also induce breast pain because of their water retention properties. Too much salt in the diet will preserve more water in body tissues and strains the breast. Recent studies have shown that animal fat can also contribute to increasing soreness in breasts. Although the exact reason is still unclear, some believe that it is linked to the animal hormones and what they were eating. Dairy products like fatty foods, the reason for dairy products inducing sore breasts is not yet clearly established. But some suspect that women who experience extreme breast pain or sore breasts after periods may be allergic to some components of the dairy products. HRT and birth control pills. Hormone replacement therapy may not be in line with what the woman actually needs. Some pills also contain additives that may produce more pain among very sensitive women. Hormonal change. This is a common occurrence, especially if you are near menopausal age. At this time, estrogen and progesterone levels become imbalanced. As in most diseases, stress is a dark force that can lead to several systemic changes that lead to pain.