Yes decongestants do help when the inner ear
pressure seems to rise. there is a tube in the ear that helps to equalise the pressure called the eustachian tube. If it is closed then the inner ear feels heavy and hearing can get impaired.The decongestants help sometimes to open up the eustachian tube.
Try using decongestant drops in your nose for a couple of days. If it does not relieve, you may need to see an ENT doctor who will find out the actual reason for your problem. He/She may have look into your ears and treat the exact problem.