Tension-type headaches are associated with muscle tension at the back of the neck or scalp, which may be triggered by stress, anxiety, anger or physical irritants such as loud noise, eyestrain (e.g. from reading for long periods of time), poor posture, or clenching the teeth.
Although the causes of migraine are not yet fully understood, they involve abnormalities in the constriction and dilation (relaxation) of the blood vessels of the head. Amongst the potential triggers are food allergy and sensitivity to certain food chemicals (e.g. amines), stress, premenstrual syndrome, flashing lights or bright glare, too little or too much exercise or sleep, and changes in barometric pressure.
Sinus headaches are symptomatic of sinusitis, which is an infection or inflammation of the sinuses (the open spaces in the bones of the skull and face). Common causes include upper respiratory infections (such as the common cold) and nasal congestion or irritation of the sinuses due to allergy and other factors. This causes an increased production of mucus, and a feeling of internal pressure, and the area becoming tender and sore to touch.
Other triggers and causes of headache include may include hormonal changes, caffeine withdrawal, discontinuing the use of some medical drugs, side effects of medication, head trauma, poor posture, blood sugar imbalance, dehydration, exposure to bright lights, computer over-use, exposure to pollution and strong smells, and underlying health problems.