The Most Common Headache:

About 90% of the headaches out there are tension headaches.  Tension headaches are usually caused by the contracting of the layer of muscle around your skull (Upper cervical), which in turn can decrease blood flow to your head.  That's why you'll feel a band of pressure around your head, and that steady pain typical in tension headaches.

Migraine Headache 

Migraine is not just a bad headache.  In fact, some people get migraine without any headache at all!  The cause of migraine is still a mystery.  The research to date seems to indicate that migraine headache is a neurological disease based on an inherited genetic abnormality.

A cause of migraine symptoms is usually called a "trigger".  A trigger is what starts the chain reaction, usually leading to migraine headaches.  If you've heard much about migraine, you may have heard about various things that happen to the body - serotonin levels (is an organic compound that is a chemical messenger known as a neurotransmitter) changes in blood vessels - a variety of things happen that cause those terrible symptoms, such as nausea and headache.   

Serotonin: In the human body, about 90% is found in the intestine, and 10% in blood platlets in the brain. The levels of this neurotransmitter in the body, too much or too little, have been linked to a number of disorders. These include depression, seasonal affective disorder (SAD), bulimia, alcoholism, cluster headache and migraine. It seems to influence mood and libido. It has an impact on blood vessel constriction. 

Sinus headache

A sinus headache, happens when you get an infection or your sinuses become inflamed.  You usually have other symptoms such as congestion, fever and fatigue. (Migraine is often misdiagnosed as sinus headache) 

Clusters are another different type of headache that may not always be a headache. Rarer than migraine, and more painful, clusters usually attack men.  The cause of clusters is also somewhat of a mystery.  Now research, is giving us clues that may crack the cluster code and provide relief.  Cluster headaches may be related to the sinuses, the nervous system, and serotonin.   

There are many more reasons why you may have a headache, and many different symptoms.  Do you get a headache after you exercise?  Are your headaches caused by allergies?  What about an ice cream headache, a thunderclap headache, or getting a headache along with a bloody nose?