There are many reasons for vague headache, such as cerebral ischemia, neurasthenia, cervical spondylosis, tension headache, brain tumor and so on. 1. Insufficient blood supply to the brain: insufficient blood supply to the brain can cause vague headaches, mainly due to blood viscosity, slow blood flow, but also may be accompanied by memory loss, dizziness and other phenomena. 2. Neurasthenia: neurasthenia has many triggers, especially in overwork, emotional ups and downs, high temperatures and other factors, can appear the phenomenon of vague headaches. 3. Cervical spondylosis: cervical spondylosis can cause vague headaches, accompanied by limited cervical spine activity, cervical spine pain, numbness of the upper limbs and other phenomena. 4. Tension headache: Hidden headache may also belong to tension pain, which may show the phenomenon of persistent, oppressive and dull pain in the head. 5. Brain tumor: If there is a tumor in the brain, there may be no obvious symptoms in the early stage, and the hidden headache may appear after the tumor grows to a certain extent. There are many reasons for vague headache, so patients are advised to go to the hospital in time to improve the examination and take standardized treatment according to the doctor’s instruction.