Breast pain is a common symptom in women. The main reason more than 50% of women come to the clinic for daily outpatient work is breast pain. How does breast pain occur? How is it related to breast cancer? It is a topic that many women want to know. Does breast cancer cause breast pain? The answer is yes, almost half of the breast cancer patients have varying degrees of vague breast pain or tingling pain that is progressively worse, and some of them involve the shoulder and back, so it is wrong to think that breast cancer is not painful. The pain of early stage breast cancer patients is usually mild, so some patients ignore the existence of pain and eventually delay treatment. About 13% of breast cancer patients have breast pain as the initial symptom, and in more than half of them, breast pain is the only early manifestation, i.e., only breast pain but no lump can be felt. At this time, further mammography, ultrasound and MRI are needed to detect hidden lesions in the breast. Most patients with advanced breast cancer have severe pain, progressive pain and lump ulceration and bad odor. Breast cancer is mostly found in women over 40 years old, so women who are older and have persistent hidden pain in the breast with fixed location and heavy shoulders are recommended to go to regular hospitals for further examination to rule out the existence of tumor in the breast so as not to miss the opportunity of early diagnosis. Breast pain can also be caused by acute inflammation of the breast, mainly manifested as localized redness, swelling and pain in one side of the breast, accompanied by an increase in body temperature, which can be reduced by antibiotics (e.g.) and hot compresses in the early stage; if an abscess is formed in the late stage, an incision and drainage is required to drain the abscess. The disease often occurs in lactating women 1-2 months after delivery, especially in first-time mothers. The germs usually invade from the nipple rupture or chancre, but can also invade directly and cause infection. The chronic inflammation caused by plasmacytosis mastitis can also cause breast pain. Sometimes the skin is red and swollen and painful to touch. The nipple is discharged with a powdery slag-like substance and smells foul. In later stages, abscesses may form and fistulas leading to the nipples may be formed. The axillary lymph nodes on the same side may be enlarged. The disease occurs in non-lactating women between 30 and 50 years of age. It has a slow onset and can also have an acute phase or a course of monstrous episodes. Ovarian tumors also often cause breast pain. This is because ovarian tumors secrete a large amount of estrogen, and these hormones can cause significant breast enlargement and incomplete replication, which can lead to pain, so patients with ovarian tumors are often accompanied by mastopexy or breast cancer. Therefore, for some patients whose cause of breast pain is not clear, ovarian examination is performed. Some patients only have breast pain without breast lumps, which is called “breast pain”. Some patients with breast pain have severe and persistent pain, such as needling or cutting; some have vague pain, and the location is uncertain; some have bilateral pain of varying severity, which can be radiated to the armpits, shoulders and back and upper limbs, and in severe cases, they cannot even dress or dare not walk. Patients with “breast pain” are often accompanied by breast hyperplasia, which can be seen as hypertrophy or granularity in the upper part of the breast during examination. Breast pain in menopausal women is mainly related to the secretion of a large amount of gonadotropins in their bodies and phytoconstriction. The treatment of this type of breast pain syndrome is better with Chinese herbal medicine to soothe the liver and relieve pain. In most cases, the pain will be relieved or even disappear after a period of treatment, but some may have recurrent episodes of lumps later, which need to be checked regularly. People can’t help but ask what to do if breast pain occurs. Patients can go to a regular hospital. After the doctor understands the medical history, he or she will first perform a physical examination to check the bilateral breast; he or she will also combine imaging examinations, including mammography (mammogram), ultrasound, and if necessary, breast magnetic resonance imaging (MRI) and gynecological examination. To rule out pain caused by breast or ovarian tumors. The final diagnosis will also be based on cytology or pathological histology. Therefore, when an abnormal breast mass is found, a biopsy, either by puncture or by surgical intervention, is needed to clarify the diagnosis and take further treatment.