I think it’s plausible that moments of intense catharsis or realisation etc can cause some kind of physical dilation, like a rush of blood or endorphins or some other kind of neurochemical which you may feel as occuring “in your brain”. I suffer from occasional BPPV and that’s how I originally felt the symptoms, like some force was squeezing my brain and it was going to implode. But I came to understand the feeling to be inflamed blood vessels surrounding my skull rather than anything to do with my brain. It was distinctly more an all-over-the-head feeling than any headache I’ve had