The causes of headaches in 16-year-old girls are mainly categorized into physiological headaches and pathological headaches. For example: excessive study pressure, bad posture, migraine, tension headache and so on. 1. Excessive pressure: high mental tension in daily life, excessive pressure will trigger headaches, can be relieved through massage, decompression and other ways. 2. Bad posture: shrugging shoulders, sitting on a chair without a backrest or with a low backrest, and not being able to straighten your back when you study can cause headaches, which can be relieved by correcting bad posture. 3. Migraine: If you do not have enough sleep or long-term stress, it will lead to migraine, mainly because of the abnormal contraction of blood vessels. 4. Tension headache: tension headache is a kind of primary headache, the persistent contraction of the muscles of the head and neck will lead to the occurrence of tension headache, mostly occurring in the crowd of mental stress and poor sleep quality. Other conditions can also lead to headaches on one side of the 16-year-old girl, the symptoms of headaches can be timely medical treatment under the guidance of the doctor to carry out the appropriate treatment.