The pain on the left side of the neck is considered to be trauma, muscle strain, cervical spondylosis and so on. 1. Trauma: If the left side of the neck suffers a violent impact, it will cause local soft tissue damage and pain, usually accompanied by redness and swelling and other symptoms. 2. Muscle strain: If you keep a posture for a long time, such as looking at a cell phone with your neck crooked, it will lead to local muscle strain and cause pain. 3. Cervical spondylosis: cervical spondylosis and degenerative disc disease has a certain relationship, on the basis of the lesion, long-term low head or work will lead to the spinal cord, nerve roots, vertebral artery and other compression caused by a series of dysfunction, the most important manifestation is pain. Pain on the left side of the neck may have other causes, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, and then give targeted treatment or treatment.