How do pilots cope with pressurization changes?
There is a chance you suffer from aerosinusitis but you should consult a physician to obtain a proper diagnosis (Disclaimer: I am NOT a doctor). For what its worth commercial planes are pressurized generally to about the pressure you would see at 8000 ft. this equates to about .75 Atm. In the reverse case 33ft underwater already has you at 2 Atm.

When I fly (generally unpressurized) I usually chew gum which i find helps.