The pain in the left side of the neck and shoulder may be caused by physiological reasons such as being cold, or by pathological factors such as fatigue injury, cervical spondylosis and myocardial ischemia. 1. Physiological reasons: If you blow air conditioner or fan for a long time in summer, the left side of your neck and shoulder will be cooled for a long time, and the above symptoms may also appear. 2. Pathological factors: the left side of the neck and shoulder has more muscles, fascia and other soft tissue structures. Long-term strain or fixed posture may lead to tension and spasm in these soft tissue areas, inducing aseptic inflammation and causing symptoms of left neck and shoulder pain. Degenerative lesions of the cervical spine may cause the appearance of cervical spondylosis, and the displacement of the cervical discs may produce jamming or pulling stimulation on the posterior and lateral posterior nerves, resulting in the symptoms of pain in the left side of the neck and shoulder; when the coronary blood supply is insufficient due to various causes of myocardial ischemia, the radiating pain in the left side of the neck and shoulder may also appear. The symptoms of pain in the left side of the neck and shoulder alone may not be able to accurately determine the cause of the pain, but also need to be combined with the characteristics of the medical history, other test results to make an accurate judgment, it is recommended to clarify the cause of the disease under the guidance of a doctor, and comply with the doctor’s instructions to standardize the treatment.