Premenstrual period, pregnancy... Hormonal changes can make the breasts more sensitive. The breast is made up of a drainage system, surrounded by connective tissue and fat that provide support. During the menstrual cycle, the nipples as well as the breasts can become painful due to hormonal changes as the breast cells and alveoli multiply in preparation for a possible pregnancy... But the reasons for this sensitivity can be multiple: a pregnancy, the rise of milk, the generous breasts, the menopause, a mammary cyst, a mammary nodule, a simple bump, the taking of certain medication...