Left chest stabbing pain may be caused by coronary heart disease, left-sided pneumonia or intercostal neuritis. 1. Coronary artery disease: patients with coronary artery disease may have pain in the precordial region, which often occurs after activity or emotional excitement, and is oppressive pain, which may be radiating. 2. Left-sided pneumonia: patients with inflammation of the left side of the lungs may experience stabbing pain in the chest, which may be accompanied by fever, cough and sputum. 3. Intercostal neuritis: it can be caused by viral infection, cold, fatigue or trauma and other factors of non-specific inflammation, the symptoms of intercostal neuritis are mainly distributed along the intercostal space. In addition, the left chest pain may also be caused by the left side of pleurisy and other reasons, the patient should promptly consult a doctor for examination, the doctor to judge, to avoid delayed treatment due to self-judgment.