it really doesn't sound a bit like altitude sickness, or a bug.....if you look up aerosinusitis or sinus barotrauma (often they use barotrauma in a diving context and aerosinusitis in flying....they are actually both the same thing), I think you will find what you are looking for...Ive had it and it is excrutiatingly painful...can cause headaches pretty much anywhere not just where we all consider our sinuses to be, as some sinus cavities are deep inside the skull and very close to the brain.
Hope your fully recovered