A Nap always helps because 1/2 the time I am under one of the symptoms listed below. Try and see if you have any of the problems listed below.
Common causes of headaches include:
Alcohol, caffeine, or other drug use or withdrawal.
Changes in the levels of chemicals in the body (neurotransmitters).
Coughing or sneezing.
Dental problems or procedures, such as pain from grinding the teeth or from a root canal.
Eating or drinking cold foods and fluids.
Exposure to smoke or fumes from chemicals, including carbon monoxide.
High altitude. Lower oxygen levels at high altitudes can cause headaches.
Medical procedures, such as the aftereffects of a lumbar puncture (spinal tap).
Medications. Many medications can cause headaches.
Muscle strain in the neck, upper back, or shoulder muscles.
Upper respiratory infections.