I read an interesting article the other day about research into brain freeze as an easy way to study headaches of certain types. It had some interesting stuff to say about the headache cause and effect with one of the brain’s major blood vessels, and how possibly they could do something just to relax the blood vessel and thus help headaches. They also confirmed that “put your tongue on the roof of your mouth to stop an ice cream headache” really does work.
Anyway, one of the main things with tension headaches is usually that your jaw gets all clamped up, which is why one of the standard DIY headache cures is to hold a pencil (latitudinally, from lip corner to lip corner) between your teeth.
I’ve currently got a sinus headache with a good chunk of tension stuck on, and I’m not really in a position to drink anything caffeinated today (my usual fast remedy). So I just tried putting my tongue on the roof of my mouth, as one does for brain freeze, and experienced a quick release of some (though not all) tension. Doesn’t do a darned thing for my sinuses, of course, but you can’t have everything.
So there’s another little trick to try until the aspirin, ibuprofen, etc. kicks in, if you don’t have a pencil or pen.