Possible Clues:

• Intense headache
• Mirage, in flickering, may give one a sort of headache
• One King George invading American state becomes a headache
• Jet fighter almost precipitated a headache
• From mare gin I get a severe headache
• What screaming may exacerbate
• I'm changing gear in another way. It's a pain
• Crippling headache
• Headache? Me, I ring a doctor
• Severe headache often accompanied by nausea