Of course I have no idea what your problem is. And while I'm not sure I ever quite raised to the level of "migraine", as I only on a couple of occasions got something like a full-blown aura or blurred vision, living with 3-4 major, debilitating headaches a week was a regular occurrence for me in my teens and 20s. (In hindsight I'm not even sure how I got through college. They mostly struck in the afternoon, so I guess I was mostly getting my life lived in the morning, which wasn't much fun since I was an evening person, due to, well, a good chunk of the things I'm about to list....)

In rough order: Discovering I had celiac disease. This was the big breakthrough without which I could make no progress, but it's not the only trigger I have.

Caffeine withdrawal; I have somewhat reluctantly dropped it from my diet because I withdraw at the drop of a hat (did you have 2.5 diet colas instead of 3 by 3pm? Headache time!) and I got tired of having to plan my days around making sure I got the right amount. (Possibly related to celiac; it can affect the speed with which things like that enter the blood stream.)

Discovering I'm not "allergic" to cashews or pistachios in the anaphylaxis sense but that they give me headaches.

Red dye 40. (Mostly in things I shouldn't be eating anyhow, but this was an extra twist of the knife.)

Poor sleeping posture; a new mattress for me was helpful, I'd recommend back exercises for everybody (specifically bridges), or at least everybody 6 foot plus.
Excessive snoring/sleep apnea.

Excessive sugar, or even just excessive simple starches; blood sugar spikes.

Dehydration. (For whatever reason, there are a number of situations in which my thirst signal is simply inadequate and I must consciously consume water. I don't die (obviously), but I get massive headaches here that do not respond worth a crap to any OTC painkiller very well. I'm still sorta trying to figure this one out to see if it's a symptom of some other underlying issue, or if it's just the way I am.)

Real root beer, for whatever reason; appears to be more than just the sugar. (This took a while since I don't drink it very often, but it ruined a couple of ice cream social-type things before I figured it out.)

I'm not sure if this was a headache trigger, but discovering that I had some major heart issues that was a total asshole and only appearing while I sleep (vagal paroxysmal atrial fibrillation), so I had almost no clue that I had the issue, almost certainly a further effect of celiac. Treated with magnesium, potassium, taurine and l-arginine, vitamin C, vitamin K, and vitamin D. (Yes, it takes almost all of those for me. Celiac is "fun" when it comes to nutrition; you "get" to learn a lot about nutrients.) The heart issue itself may have been causing headaches directly, it certainly indirectly contributed to the several reasons my sleep has been poor for most of my life.

I recommend trying something like an elimination diet: https://greatist.com/grow/easy-elimination-diet-for-food-int... That particular link describes more of a "medium effort" sort of thing; you can also go whole hog and eat nothing but simple meats, fruits, and veggies for a while, and slowly fold things back in over weeks. It's extreme, but if you are someone who is sensitive/allergic to, say, soy, wheat, and dairy, it's really the only sane way to find that out. It blows to find out you've got one or more of the "major allergies" but it's a hell of lot better than not knowing!

Plus there's a chance you do the full elimination diet and it doesn't affect your migraines at all; well, you pretty much eliminated food issues in one fell swoop. Still a win.

Also grab a sleep recording app for your phone and record the audio of your sleep. I'm not sure science is 100% here yet but it seems to me we're going to end up in a place where basically all snoring beyond the most minor indicates bad sleep. If you've got a lot of snoring or any other sign your sleep is compromised, see about getting into a sleep study. In fact I pretty much just uniformly recommend everyone who has not done this do it, because the cost is virtually nil (the apps are free and it takes 5-10 minutes top to set this up for a night) and the potential benefits large; it's worth doing for anyone who isn't 100% sure they're awesomely healthy. If nothing else, the costs are so low it's just worth it to satisfy your own intellectual curiosity about how well you're sleeping; if you discover it's great, well, now you know, which is nice.

As you may have guessed from the previous paragraphs, it took me about 5-8 years to work it all out. But I have gone from being rocked by headaches almost continuously to pretty much never having a headache without knowing exactly what I did wrong, what I should have done instead, and how to prevent it in the future. Losing an evening to headaches is now almost always because I did something stupid, rather than inexplicable life.