Can't stand the pressure

My father felt the same thing when he flew abroad for the first time. It's due to the adjustment of our bodies to the air pressure. The lower we reside on earth the higher the air pressure - and if you are flying the air pressure is lower because the air is thinner up there (that's why airplanes are pressurized and that's why you can't open the windows on a plane). Since we are accustomed to higher air pressures at sea level, our bodies adjust to the lower air pressure. And if we suddenly experience adjustments, we feel the pain. My father just drank a cola drink and burped to force the release of the extra air in our ear resulting from changes in air pressure. The ear, by the way, governs our sense of balance by maintaining constant air pressure inside our inner ear. Just try to burp in order to release the air which is the cause of the pain. You can also experience this riding an elevator that moves so fast when going up or down. What I do is I open my mouth to prevent the air pressure in the ear into accumulating. Or I force a burp.