Why do ears ache during landing of a plane?

Answer 1

The plane changing attitude cahnges the air pressure. The air pressure difference between your outer ear & the inner ear is what cause the pain. The inner ear can't regulate the pressure that quickly.

Answer 2

Your ears ache during plane landings for a simple reason. At higher altitudes, air has lower pressure. At ground level, however, the pressure is much higher. When there is a change in pressure, there is a change in the volume of the air in your ear drums. This is what causes the pain. However, chewing gun often helps because the jaw motion often helps to equalize pressure more gradually.