There are not only 4 reasons that can cause left neck pain, it may be due to long time fixed keep bad posture to play cell phone, play computer, etc., caused by the left neck muscle spasm. Patients can first use hot towels for hot compresses or massage to promote local blood circulation, relieve muscle spasm and improve the symptoms of left neck pain. In addition, patients with neck pain on the left side also need to be alert to whether it is caused by the drop pillow, cervical spondylosis, lymph node inflammation, frozen shoulder and other pathological reasons: 1, drop pillow: patients feel pain, stiffness and limited activity in the left side of the neck when they wake up in the morning, mostly due to poor sleep posture at night, or feel wind and cold caused by the drop pillow; 2, cervical spondylosis: cervical disc protrusion, cervical spine osteophytes and other cervical degenerative changes, resulting in Most patients also show symptoms such as left upper limb radiating pain, dizziness and headache; 3. The symptoms include fever, chills, fatigue, and mental discomfort. 4. Frozen shoulder: Frozen shoulder is common in patients around 50 years old, and is typically characterized by pain around the shoulder joint and limited movement of the upper limbs. In some patients with left-sided frozen shoulder, the pain can also be radiated to the left side of the neck. In addition, thyroiditis, left lymph node tumor, neck boils, shoulder joint lesions and other pathological causes may cause pain in the left side of the neck, which requires medical attention for differential diagnosis and thus targeted treatment.