All these head feelings are coming from dysautonomia, in my experience. I’m now 60, suffering from these issues since childhood, however never understood them till lately when my condition worsened after 3 years of long flights every month.
Here is the explanation, as I see it: Dysautonomia causes nerves over reaction to what we eat, so there is a pull on nerves across whole body, and depending on body constitution, pronounced in certain areas- head in my case. So these nerves pull on the brain itself as well, since a lot of these nerves connect to our brain. This is the reason behind