Task: Question Answering
Input (English): Context: Then the pain kicks in , usually on one side of my head in my temple . My migraines almost always occur during a period of relaxation immediately after a period of high stress . Normally they 're somewhere between 6 and 18 hours of excruciating pain , followed by a day of feeling like I ' ve been hit by a bus . 
Question: What may be the reason why their body experiences migraines after stress ?
Output (English): Because their body is so tense .