There are tests that can rule out other causes of headaches. Typically the first headache of this type begins between the ages of 10-30. Most people would describe these as severe, rather than mild to moderate. They often feel disabling. They are usually associated with light, noise and motion sensitivity.
Nausea is usually a component.
Typically you want to close your eyes in a quiet place and sit still. A medical provider should check out a severe headaches you find clearly different than your usual headache pattern. Uncommonly a visual sensation or feeling called an aura will precede the headache. The headache may be pounding or behind the eyes. It may be on one-side of the head.