What causes you to get a headache?

  Many kinds of reasons cause me to have a headache. Such as, lack of sleep, get ill, bad living habits .When I play computer games late in the evening, I must get up early in second days, and I will feel a headache that day. When I have a sick, fever, blood pressure will also cause headaches. When I don't have a good diet habit or stop exercise also can lead to headaches.