It is recommended to go to the hospital to complete the relevant examinations to exclude organic lesions of the chest wall and chest cavity tissues and structures, and further treatment and management. 1. One month’s constant pain over the left breast is commonly associated with non-specific costochondritis, the cause of which is not known, but is self-healing. 2. Female left breast disease such as breast hyperplasia, early breast cancer and other lesions can also cause occasional hidden pain, need to perform chest wall ultrasound and other tests to clarify the diagnosis and further treatment. 3. Diseases such as chest wall bone tumors above the left breast can also cause occasional hidden pain, which need to improve the relevant examinations to clarify the diagnosis and further treatment. 4. Intrathoracic diseases such as pleurisy, lung infection, lung cancer, etc. can also cause occasional vague pain in the upper left chest, which also needs to be further treated after complete relevant examinations for clear diagnosis. It is recommended to go to the hospital for further counseling or treatment if you have been experiencing pain in the upper part of the left chest for one month.