Sitting for a long time after the back of the neck pain is usually due to pathological factors, common causes are muscle strain, cervical spondylosis, myofasciitis and so on. 1. Muscle strain: If you sit for a long time, the neck muscles in a static position under constant tension, such as long-term head down to look at the phone, it is easy to lead to chronic cumulative injury to the neck muscles, showing persistent pain in the back of the neck. 2. Cervical spondylosis: cervical spondylosis is due to long-term cervical spine strain, and then degenerative lesions, so that the cervical nerve roots, vertebral artery pressure, cervical spine dysfunction. After sitting for a long time, if the posture is not appropriate, the cervical spine force increases, it will aggravate the symptoms of cervical spondylosis, showing the back of the neck pain. 3. Myofasciitis: Myofasciitis is an aseptic inflammation of soft tissues such as muscles, fascia, tendons and ligaments. After sitting for a long time, if the neck muscles are in a persistent state of contraction, long-term muscle tension may lead to muscle spasm, appearing after sitting for a long time back of the neck pain phenomenon. In addition to the above reasons, trauma and tumors and other diseases may also cause pain in the back of the neck. If the pain in the back of the neck after sitting for a long time cannot be relieved by oneself, it is recommended to go to the regular hospital to take appropriate treatment according to the cause.