Soreness on the left side of the shoulder and neck can be caused by the following reasons: First, cervical spondylosis, when cervical spondylosis is cervical cervical spondylosis, there can be soreness in the left side of the neck and shoulder muscles. The pain is often more obvious or aggravated when you get cold or when you keep your head down for a long time. When the suprascapular nerve is stuck due to fracture or tumor compression, the nerve can be compressed, resulting in soreness and pain, then we should check the electromyography of the suprascapular nerve as well as physical examination for early diagnosis and treatment.