My ears have crackled and popped for the last 2 years. My ENT (who I was seeing for treatment of thyroid cancer) told me not to worry about the popping. My cancer was "cured" but now I have a constant fullness in my right ear that feels like I'm under water or on an airplane coming down. I have been to my GP twice and she said she sees no fluid build up. I went to an audiologist who also said that though my hearing might be a bit muffled, it is within the "normal" range and she also couldn't see any fluid build up. I am worried that somehow this is related to my thyroid cancer.