My ears feel clogged when I'm on the airplane. Is this normal? Is there a medication for this?

Normal. This is related to eustachian tube dysfuntion. You can try clearing your ears with the valsalva manuever (also used in diving). Afrin (oxymetazoline) before the flight may help, yawing, chewing gum can help as well. All of these attempt to allow the eustachian tube to open to relieve the pressure.
Pressure change. This is normal and quite common due to pressure changes between your sinuses and the cabin. Try chewing or swallowing frequently which works for me (and i'm a pilot too).