This type of pain is often caused by a muscle strain or spasm in the upper back and neck area, sometimes triggered by poor posture, sudden movement, or sleeping in an awkward position. It may also occur due to acute torticollis, a condition in which the neck muscles tighten and restrict movement. In some cases, age-related changes in the cervical spine, such as cervical spondylosis, may contribute. If the pain is severe, persistent, or accompanied by numbness or weakness, please consult your doctor promptly.