Hi Leigh Ann,
I have the same frustrations. I have been sticking as closely as possible to the Migraine Diet outlined in the book Heal Your Headache: The 123 Program For Taking Charge of Your Headaches by David Buchholz M.D. After I had been on it a while I added back things I thought didn't bother me and was quite successful. This list is good for foods. As for other things my neurologist provided me with this list:
Job Loss / Change
Let Down Period
I think there is ambiguity in the lists because it's different for everyone. For me caffeine is deadly, but I've read about people who find it helps them. Stress is also an immediate trigger for me, though there was a time when I could work 6 or 7 days a week for 12 to 14 hours without getting a headache. For me dairy isn't a trigger though the bacteria in yoghurt and aging process for cheese are killers. Dairy will create more mucus and cause sinus problems which can trigger headaches and if you're lactose intolerant will cause stomach problems.
I hope this helps a bit. I empathize with your frustration. I can't seem to stay away from all of the triggers, though I try. If you read or have read the book I mentioned MSG comes in all forms and staying away from it is really difficult, though I notice how much better I feel when I do.
The secret of health for both mind and body is not to mourn for the past, not to worry about the future, or not to anticipate troubles, but to live in the present moment wisely and earnestly. Buddha