The majority of breast pain is the cause of the first visit to the breast clinic, followed by breast lumps. The correct diagnosis and differential diagnosis of breast pain can reflect the professionalism of the mammographer. Sensation in the breast is innervated by the intercostal nerves and the 3 and 4 cervical nerves, which can cause pain once these nerves are violated, so breast pain is not a specific symptom of a particular disease. Breast pain mostly comes from benign non-tumor breast lesions. Early stage breast cancer rarely presents with pain unless it is locally advanced or inflammatory breast cancer. Therefore, breast pain is not proportional to the benignity and severity of the breast disease. What breast diseases can cause breast pain and how to identify them? There are more diseases that cause breast pain. In the face of a patient with breast pain as the main complaint, we should carefully inquire about the medical history, whether there is any trigger, the onset and duration of pain, the characteristics of pain, whether it is treated and what the effect is, and then conduct physical examination. The following cases are common. 1, postmenopausal breast pain: breast pain occurs in a few postmenopausal women because the breast tissue cannot adapt to the rapid decrease in endogenous estrogen secretion, and may still feel pain or feel nodules in the breast for a period of time after menopause, which belongs to a physiological change, but should never be careless. If you have hidden breast pain and lumps after menopause, you should be highly alert to the possibility of breast cancer, and you should use imaging or cytological examination for differential diagnosis. 2. Nipple cracking: It often occurs in breastfeeding women and is caused by local trauma to the nipple when the baby sucks on the nipple. The nipples are in severe pain when breastfeeding. Plasmacytoid mastitis is often accompanied by nipple indentation, subareolar lumps, local itching and burning pain. 4.Breast cancer: most of them are not accompanied by pain, only a very few patients feel slight discomfort at the tumor site, individual patients have pain, and the attacks are often irregular; advanced breast cancer tumors invade nerves or breast cancer tumors break down and necrosis to form ulcers will appear burning pain, persistent and progressive aggravation. Inflammatory breast cancer usually has no symptoms of systemic infection, no fever, and the skin may show redness, swelling, heat and pain with pressure pain. Routine blood tests do not show high white blood cell count, antibiotic treatment is ineffective, and puncture can find tumor cells but not pus. 5, acute mastitis: most of them occur during the lactation period, before the onset there is often nipple cracking, feel nipple pain when breastfeeding, continuous pain, sometimes you can see individual milk duct opening obstruction, poor milk discharge, milk stagnation, the formation of hard nodes, causing swelling and pain, continue to develop can appear systemic symptoms such as fever, loss of appetite, headache, and even chills or chills. Routine blood tests may show elevated white blood cell count and increased neutrophil ratio. On physical examination, the breast may be red and swollen with blood, increased skin temperature, significant pressure pain, and palpable lumps with poorly defined boundaries. If the inflammation is not treated in time, the abscess will be formed by cellulitis, and there will be fluctuating sensation on palpation. Eventually the abscess will break down, or the pus will be discharged from the nipple through the milk duct, or the abscess will be cut and drained, and the pain will be significantly reduced until the wound heals and the pain is relieved. Based on the clinical manifestations of skin redness, swelling, heat and pain with systemic toxic symptoms and the history that often occurs during lactation, the diagnosis of acute mastitis is not difficult, but caution must be taken to differentiate it from inflammatory breast cancer. 6. Mammary gland hyperplasia: It occurs in women aged 30-50, and is less common in adolescence or after menopause. Mammary gland hyperplasia is neither a tumor nor an inflammatory disease, but a disorder of endocrine secretion in the body, resulting in excessive hyperplasia and incomplete replenishment of the breast parenchyma or interstitium. The clinical manifestations of mammary gland hyperplasia have different characteristics at different ages. In unmarried women or married women who have not had children or are not yet breastfeeding, the main symptom is breast swelling and pain, which can involve both sides at the same time, but mostly one side is heavier. The pain is often cyclical, with the swelling and pain in the breast being obvious before menstruation, relieved and gradually disappearing on the second day after menstruation, and reappearing before the next menstruation, with a diffuse nodular sensation in the whole breast, and accompanied by tenderness. The main symptom in women after 35 years of age is breast nodules, which are less painful to palpation and have episodes unrelated to the menstrual cycle. The nodules may be found on palpation of the breast as flat, round or irregularly shaped, tender nodules of varying size, with unclear borders and no adhesions to the skin or deeper tissues, which can be pushed. after the age of 45, they often appear as single or multiple scattered cystic masses with clear borders and are often accompanied by dull, swelling or burning sensations. In the differential diagnosis, intercostal neuralgia caused by costochondritis, discomfort in the precordial region caused by insufficient coronary artery blood supply, pain in the back of the shoulder caused by frozen shoulder, and physiological breast pain in lactating women with distended milk should also be considered. Benign tumors of the breast are usually not associated with pain. The main symptom of intraductal papilloma is nipple discharge, and most of them are not accompanied by pain, but only when the tumor is large and obstructs the milk duct, pain and lump may appear.