Hi Ginger;
Sorry you had problems & needed to change screen names.
I don't have migraines myself, but my dw had them for many years and has been free of them for a while now after some careful checking. In her case it was a spinal issue where an old injury and posture combined. She got good relief from an initial Chiropractor resetting the injured vertebre area repeatedly until the muscles and posture could become more comfortable in the new positions.
My kids have once in a while reported big headaches that were enough to limit their activity and lasted for hours. For our family, this is not common but I cannot project that into anything like the statement that neurological disorders do or don't come with migraines.
You probably already know most of what it says, but there is a good summary on the Mayo Clinic site, including some of the alternate medicine approaches that have helped others:
http://www.mayoclinic.com/health/migraine-headache/DS00120 It mentions herbs, vitamins, minerals, but we have found that food preservatives and some coloring/flavor additives seem to also be related.
Good luck tracking down the things which will help, and helping your ds to learn what might be warning signals or ways he can reduce or shorten the time for the pain.