Left side throat pain may be caused by laryngeal cancer, hypopharyngeal cancer or other diseases such as acute or chronic laryngitis. 1. Laryngeal cancer: laryngeal cancer is a primary malignant tumor of the larynx, when the cancer spreads to the left hypopharyngeal structure area, symptoms such as discomfort in the throat, pain in the left larynx and sometimes hemoptysis or sputum with blood can occur. 2. Acute and chronic pharyngolaryngitis: acute pharyngolaryngitis is an acute inflammation of the mucous membrane of the pharynx, which is often the result of viral or bacterial infection, and it can also be caused by allergy, damage of foreign objects, excessive pronunciation, etc. Chronic pharyngolaryngitis refers to an acute inflammation of the mucous membrane of the pharynx. Chronic pharyngolaryngitis refers to chronic non-specific inflammation of pharynx, which is related to inhalation of toxic gases and dust, spreading of chronic inflammation in nasopharynx and excessive use of voice. 3. Hypopharyngeal cancer: mostly squamous cell carcinoma of hypopharyngeal mucosa, which often occurs in the posterior cricoid region, pyriform fossa, lateral part of cleft and other parts of the pharynx, and it can have the symptom of sore throat after its onset. It is recommended that patients with persistent pain in the left side of the throat should go to the hospital as early as possible to find out the cause and then give targeted treatment.