The causes of pain on the left front side of the neck include pillow fall, cervical spondylosis, and neck muscle strain. 1. Falling pillow: due to improper head and neck posture during sleep, pillow height discomfort or external wind and cold, thus causing stiffness and pain in the neck muscles. 2. Cervical spondylosis: a degenerative disease, mainly due to cervical osteophytes, ligament thickening, cervical spinal stenosis, etc., which causes pain on the left front side of the neck. 3. Neck muscle strain: due to the cervical spine for a long time to maintain a position, or neck muscle stretching, can also cause the left anterior side of the neck pain. In addition to the above reasons, thyroid gland lesions can also cause left anterior neck pain. 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.