I've found that avoiding processed foods, added sugars and flour (in that order of importance) really helps me with chronic migraine and fibromyalgia pain.
The way I look at it, there are so many thousands of additives in highly processed foods, there is no way I can figure out which ones might be affecting me. So I cut them all out. My goal is to eat 80% homemade food, and I generally meet that goal. I also eat organic to cut down on chemical exposure.
I've tried cutting out gluten, but it didn't make a difference for me, maybe because I don't tend to eat a lot of gluten in my normal habits.
I have to be really careful how much sugar I eat. It seemed unfair at first, but now I like eating this way - everything else tastes better when I am not bombarding my poor taste buds with too much sweetness.
I eat Dairy, eggs and meat. I make sure I get them from healthy sources. I'm not naturally much of a meat eater, but I try to eat some concentrated protein each day.
I wish you the best finding a diet that works for you. Let us know what you find out