That is a most unfortunate problem to be dealing with on such a regular basis! Allergies are bad enough with just the runny nose symptoms, but when they start to affect your hearing and your ears, it is adding insult to injury
. Yes, the inflammation and extra mucous that allergies cause in your airway are enough to cause fluid to back up in your eustachian tube, which of course leads from the back of your throat all the way to your inner ear. When you have this eustachian tube dysfunction, your hearing will sound muffle, and you just wish that your ears would "pop." While there could be something else causing your problems, it is definitely possible that allergies could be the main problem.
You sound like you are already on top of the first line steps for symptom improvement: an intranasal steroid for baseline control of allergy symptoms, with an anti-histamine for the days or weeks that are especially bad. Alternating anti-histamines (such as by trying cetirizine, for example) could improve your symptoms, and the additional of nasal saline irrigation might help. There are anti-histamines that work better at decreasing mucous as well, but they often have the side effect of drowsiness. If saline irrigation and changing over the counter meds doesn't help, please see your allergist or otolaryngologist
(aka ear-nose-and throat surgeon
) for additional treatment options.