The common causes of men’s left breast pain under pressure include gynecomastia, intercostal neuritis, herpes zoster, etc., and they need to go to the hospital to find out the cause of the disease in time. 1. Mastitis: The main clinical manifestations of gynecomastia are redness, swelling, heat and pain in the breast. 2. Intercostal neuritis: Intercostal neuritis is an inflammation of the intercostal nerves caused by microbial infections, often resulting in pins and needles or burning pain in the area innervated by the intercostal nerves, aggravated by deep breathing and coughing. The patient may show symptoms of pressure pain under the breast. 3. Herpes zoster: Herpes zoster is an acute skin disease caused by varicella zoster virus, the main symptoms of herpes zoster are rash and pain. When the virus invades the nerves in the chest, patients may experience symptoms such as pressure pain under the chest. In addition, male breast trauma and breast fibroma may also show similar manifestations. When patients experience discomfort, they should go to the hospital immediately.