The following headache symptoms mean you should get medical help right away: A sudden, new, severe headache that comes with: Weakness, dizziness, sudden loss of balance or falling, numbness or tingling, or can’t move your body.The brain tells you when other parts of your body hurt, but it can‘t feel pain itself. Most headaches happen in the nerves, blood vessels, and muscles that cover a person’s head and neck. … These nerves send a rush of pain messages to the brain, and this brings on a headache.Symptoms. A dehydration headache can feel like a dull headache or an intense migraine. Pain from a dehydration headache can occur at the front, back, side, or all over the head. Unlike a sinus headache, a person experiencing a dehydration headache will likely not experience facial pain or pressure.