What Your Headaches Can Tell You About Your Health =

Having a headache is a pain—literally and figuratively. And it’s even worse when your headaches feel constant and as if pain is nagging you all the damn time. You might be surprised to learn that there’s a fairly lengthy list of causes of constant headaches. Some reasons behind chronic headaches are not serious, while other causes can signify a deeper health issue is at play.

What causes a headache?

Experts don't completely understand what's happening in our skulls when a headache hits, but the most likely explanation is that something causes the blood vessels to swell, subsequently stretching the nerves around them and firing off pain signals.

Cluster headaches: This type occurs usually on one side of the head, causes one eye to tear, and leaves you feeling extremely agitated. They are not very common and seem to run in families, Dr. Hutchinson says. An “attack” may last weeks or months, according to the Mayo Clinic.

The cause is unknown, but cluster headaches may occur if something with the body’s biological clock is off, per the Mayo Clinic. Also, cluster headaches generally aren’t triggered by certain factors, like stress or hormonal changes, the way tension headaches and migraines can be. (The exceptions: Certain medications and alcohol may trigger cluster headaches, per the Mayo Clinic.)

Migraines: Migraines typically cause pain (sometimes so intense that it affects a person’s ability to function) on one side of the head and possibly nausea and/or sensitivity to light, the Mayo Clinic explains.

It’s not totally clear what causes migraines, but it’s possible that they have to do with “changes in the brainstem and its interactions with the trigeminal nerve,” the Mayo Clinic says. (Changes in serotonin levels in the brain may also play a role, but more research is needed to determine how and why.) Experts believe migraines are primarily genetic.

Tension headaches: Anyone can get a tension headache, which is caused by muscle tightness in the head, neck, or scalp, according to MedlinePlus. "Unlike migraines, which we think are genetically predisposed, tension headaches are pretty universal," Dr. Hutchinson says.

Tension headaches can be caused by everything from dehydration and workplace stress to undiagnosed diabetes or an autoimmune disease. A tension headache feels tight, like your head is in a vice, and can occur on both sides and commonly hits later in the day as tension builds. "It's a tight, oppressing feeling," Dr. Hutchinson explains.

So what does it mean if your headaches are constant or chronic?

1. You're stressed.

2. You're dehydrated.

3. You're anemic.

4. You have a chronic disease.

5. You’re dealing with hormonal issues, like menstruation.

6. You have a sinus problem.

7. Your body clock is off.

8. You drink too much caffeine.

9. You're taking too many headache meds.

10. In rare cases, constant headaches could be a sign of a brain tumor.