Just wanted to share my experience because I, like others, got to be very desperate until about 3 years ago when i finally made a breakthrough. I have had migraines for over 55 years(since 10 years old) and in later years also developed chronic daily headaches of less severity than the migraine but actually more disabling because of the frequency. Was in a sorry state. I tried everything preventative over the years and nothing worked(except maybe magnesium a little). Triptans helped my migraines but obviously could not take them for daily headache. Also i was taking one triptan a week on average and they caused side effects. Anyway my headaches are 95% less now (been ok now for about 3 years) and i very seldom take a triptan - an occasional ibuprofen is all i seem to need.
The solution for me was nicotine. I use e-cigarettes rather than tobacco but patches, lozenges etc would probably still work. In fact i think tobacco rather than pure nicotine could even make things worse so best avoided.
Will not work for everyone but if you are desperate like i was then maybe worth giving it a try. It works for me as a preventative (i.e will not cure a headache once started).