Left clavicle pain on pressure may be related to strain, clavicle fracture, malignant tumor and so on. 1. Strain: people who lack exercise for a long time, sudden strenuous exercise or heavy physical work, so that the local ligament injury or inflammation of the fascia, resulting in chronic strain, which induces osteochondritis, manifested as clavicle pain by pressing. 2. Clavicle fracture: after the left clavicle fracture, due to the dislocation of the bone, local bleeding, and resulting in tissue swelling, which can be accompanied by obvious pressing pain. 3. Malignant tumor: due to the progress and metastasis of the tumor, the lymph nodes in the supraclavicular fossa can be invaded, which will be accompanied by the symptom of clavicular pain. There may be other reasons for left clavicle pain, such as improper exertion of the left arm, long time maintaining bad posture, osteophytes, etc. It is recommended to go to the hospital in time, improve the examination to clarify the cause of the disease, and then give targeted treatment or therapy.