Why won't my ear pop?

I was on a plane coming back from visiting my grandparents for Thanksgiving Break. I had been slightly sick during the time I was there, but they all seemed like they were due to allergies (coughing and phlegm that went away within 4 days, then runny nose/sneezing that lasted about 2-3) . On the plane, right before we descended, both of my ears got the feeling that they needed to be popped, but then were followed by intense pressure and pain in both ears. I assumed it was either because of the allergies or the pressure from being so high up. Sure enough, the pain subsided when we landed. But, one of my ears can't seem to 'pop' ever since the plane ride. I've tried chewing gum, holding my nose/closing my mouth and exhaling firmly, and nothing seems to work. I don't think it is earwax because my other ear seems to be fine, and I don't see any running or earwax on the inside of my ear. Any ideas on how to clear it up? Should I go to a doctor?