Pain in the left side of the neck may be due to the following reasons First, in daily life, excessive strain on the neck, such as prolonged head-down work or prolonged stimulation by wind and cold, as well as the recent fire can lead to neuralgia in the neck; second, it may also be due to strain and spasm of the musculofascia of the neck, which triggers the pain when pressing the left side of the neck; third, due to cervical spondylosis or thyroid disease, which triggers the patient to have pain in the neck. After this happens, the patient can take oral medication to relieve the pain, such as diclofenac sodium extended-release capsules, and then give local hot compresses and local massage.