hearing aids and muffled hearing

I wear hearing aids.  Only in my right ear I have a feeling of a "plugged ear".  It only occurs with my hearing aid; not when I'm wearing head sets or have the aids out.  It comes and goes.  If I insert my aids in the moring everything might feel normal.  Then after being exposed to slight noise (the microwave oven, radio in the car) the right ear slowly begins to feel pugged up.  I try to overcome the feeling by turning up the volume on the right aid and lowering the volume on the left...sometimes that helps.    My audiologist has adjusted and reprogrammed the aids many times without correcting the problem.  This phenomenom has occurred with the last three sets of hearing aids I've owned.  It's always just the right ear and not all the time.  It's very uncomfortable and difficult to predict.  When the sensation does not exist my hearing (with the aids) is clear and crisp.....then slowly the ear plugs and the hearing resolution in the right ear diminishes.....  any comments??