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Could be a number of things, but one that hasn't been mentioned is vascular headaches. These occur when the blood vessels in your brain spasm and cause intense migraine-like pain. I used to get them alot. tricyclic antidepressants and vasoconstrictors tend to help regulate the arteries. They can be triggered by working out (temporary,high bp exercises) or medications such as clen and other asthma meds. Might want to ask your doc.
