Leaving it here for others they may strugle with this kind of thing and perhaps, blizzard will take notice of this and put a little note next to it in the options.
For very long time I use to get headaches from playing WoW at some point, only from playing WoW.
The thing that in my case is cause of this is “Rotate minimap” option. If its ON, the map motion withing the game gives me headaches. If its off, I can normaly play without any problems.
Little thing with powerful impact.
So there it is. Rotate minimap may cause headaches/discomfort with some people.
Took me some time to figure this out.