There are a few genetic factors that can contribute to it. I'm lucky enough to have most of them, so it's been a journey figuring this out. What got me on the right track was trying a low histamine diet for a week, and all kinds of not-quite-allergy things I had experienced my whole life began to clear up.
The exact list of foods varies a bit depending on the resource, but here's a pretty good one.
I have high hopes for Light No Fire.
Right now I find Cyberpunk 2077 surprisingly pleasant to wander around in. Sure it's dangerous, but when you're so chromed to the gills you can shake off a high speed collision there isn't much threat.