There are many reasons for turning the neck and left shoulder pain, and the common ones are cervical spondylosis, falling pillow, muscle strain and so on. 1. Cervical spondylosis: a clinical syndrome resulting from cervical spine degeneration, can compress the cervical nerve root neck pain, accompanied by shoulder and upper extremity radiating pain, when the head posture is not appropriate, turning the neck can appear pain. 2. Falling pillow: such as poor sleeping posture, improper pillow, etc. may cause soft tissue injury in the neck, which may result in turning the neck to involve the damaged muscles and fascia, such as the left side of the damage, there will be pain in the left shoulder. 3. Muscle strain: such as long-term head down and other bad posture, so that the muscles for a long time, continue to maintain the same posture or action, can cause neck and shoulder muscle injury, gradually appear pain, weakness, soreness and other symptoms. When turning the neck, pulling the damaged muscles can appear left shoulder or right shoulder pain. Turning the neck left shoulder pain may have other reasons, it is recommended to go to the hospital in a timely manner, improve the examination to clarify the cause of the disease, under the guidance of the doctor to give targeted treatment.