I read your quote from http://www.medhelp.org/posts/Ear--Nose--Throat/Eustachian-tube-dysfunction---what-are-the-symptoms/show/7331#post_comment and was wondering what ever happened with your thyroid problems. How are you feeling now?
Did you ever figure out what was wrong. I to suffer from exactly what you describe.
Just a quick note to say hi! I thought you might like to know that I had very similar problems which eventually led to constant pain and several doctors making out that I was a hypercondriact. It turned out that it was a cholestitoma of my right middle ear and the only way to diagnose this was to get a catscan done on my middle ear regine (masteiod area of the middle ear). Aparantly sinus issue can also cause very similar things so I would either see your gp about a ct of the sinus and middle ear regine or an ent specialist about it all. Good luck.