ISISISISISISISISISISISISISIS

Ear pain does not only happen when decending. It may happen even climbing. The main reason is the unbalance of pressure between middle ear chamber and outer ear chamber. Actually, there is a path link between ear middle chamber and month. It is used to ensure the pressure between middle chamber and outer chamber of ear are the same. However, sometimes it cannot adjust the pressure fast enough so it causes ear pain. The quickest way to overcome ear pain is drink a water or swallow. When you open your month, the air pressure will go through the path and restore the middle ear pressure as the same as outer pressure then the ear pain will disappear.

Because the pressure change, the atmospheric pressure increases when the aeroplane is descending, but the air pressure inside the ear doesn't change. Thus, the air pressure of the both sides of the ear drum is not balanced, the ear drum is forced inward. This is enough for painful signal to be created.