Some people will experience pain in either their ears or nasal cavity. It usually is not felt while the plane is in the air. It usually is felt at the beginning and ending of the flight. This pain is caused by decrease or increase in altitude and pressure in a quicker way than normal. For example, if a plane should decrease altitude suddenly and quickly, then the pain in the ears would be even more painful.
To try to relieve the pain, there are a couple of things you can do. First, you can take some regular allergy medication prior to the flight. I would recommend taking the medication a few hours before the flight. You could also eat candy or chew gum during the descent.