Pain in the area below the left collarbone and above the breast is often considered to be caused by fibrocystic breast changes, also known as fibrocystic breast disease or mammary gland hyperplasia. This is a benign condition related to estrogen levels. Breast pain typically occurs when hormone levels rise before menstruation and usually subsides on its own after menstruation ends as hormone levels decrease. If the pain is severe, oral Chinese herbal medicines such as Rujiling or Xiaoyao Wan can be taken for treatment. Additionally, since the painful area is located in the chest region, other conditions such as myocardial ischemia, pneumothorax, or pleuritis could also be possible. It is recommended that patients visit a specialized hospital for examinations, including a chest X-ray, 24-hour Holter monitor to rule out cardiovascular and pulmonary diseases, and a breast ultrasound to confirm the diagnosis and guide treatment as early as possible.