I had blocked ears last year. I am immunosuppressed and I got a really bad infection about a year ago that I couldn't shake. I found out that if you get an ear infection, sometimes that mucous in your eustacian tubes gets really thick and hard to clear even after the infection is over.
My doc recommended chewing a xylitol gum three times a day for at least fifteen minutes. Xylitol for some reason thins that mucous and the chewing helps to work that eustacian tube. In ten days, without more antibiotics, my ears cleared wide open.
My only caveat is that the xylitol can give you an upset tummy with diahrea. Trident is a xylitol gum but if you check a local health food store you might find some others. I have one that is very high in xylitol and it really has helped me.
Good luck!! Clogged ears is a horrible feeling!! It is like having your head in a box!! I hated hearing myself swallow or breathe.
Oh by the way....xylitol is very toxic to dogs. Keep it away from pets.