Hello, The cause of migraines is not well understood but we know that there are alterations in blood flow and electrical activity in the brain. Prior head or blast injuries do increase your risk of migraines, but I doubt that it is a direct cause. Other types of ailments can trigger migraines such as poor sleep, obstructive sleep apnea, excessive caffeine consumption, erratic eating habits and certain food as well as a sinus infection. Migrianes typically begin in the teenage years, but can start any time during your life. Given that it sounds like there has been a change in your prior headaches, I would recommend that you see a doctor, preferably a neurologist for a thorough examination to make sure nothing else is being missed. Hope I have answered your query. Let me know if I can assist you further. Regards, Dr. Janne Nissinen, Neurologist