A headache that occurs after looking at a cell phone for a long period of time is mainly due to neck strain and cervical spondylosis after looking at a cell phone for a long period of time. Headache is one of the most common symptoms of cervical spondylosis. Why does cervical spondylosis occur headache? There are two main reasons: 1. After looking at the cell phone for a long time, it leads to strain and aseptic inflammation of the muscles, ligaments, fascia and other soft tissues in the neck. These inflammations will stimulate or damage the nerves that innervate the head and cause headaches.2. After watching cell phones for a long time, it leads to neck fatigue and misalignment of small joints in the cervical vertebrae. These misaligned small joints will compress the nerves from the cervical spine that innervate the head and cause headaches. In short, you should not look at your cell phone for a long time. If you have a headache, stop looking at your cell phone immediately, rest your cervical vertebrae, and get appropriate examinations and treatments if necessary to relieve your headache.