Do Intermittent Clogged Ears Indicate An Allergy?

Question: I contacted you about 5 days ago stating that I bought a new house (although I'm not living in it yet) and was having an issue with clogged ears after going in the house. I was having mild nasal issues too but the ears were the bigger issue. I do regularly have allergies but not ear problems. I have in the past had times with ear clogging but it has been a few years. The prior week I had been in the house twice. Both times I was fine while in the house but then shortly later (about an hour) the ears began to feel clogged and my hearing was a little diminished. The nose was a little drippy but it was not that big a difference.

My ears cleared for a few days. I went back to my ENT and she said they looked fine. However, the clogging then came back (once yesterday for a little while and then again today). I'm wondering if this means they never really fully cleared and this is still a prolonged reaction to having been in the house last week or if it is more likely that the ear clogging just has to do with my general allergies and has nothing to do with the house? They did feel completely clear for those few days. I think now when they get clogged my nose is usually a little clogged too. Sometimes driving up or down steep hills makes them worse.
I'm also wondering if Mucinex or any other treatment will help. Thanks.