SJ..my internal tremor,as i call it, is a bit hard to explain. The best way I can describe it, is a feeling of an internal shaking, from the inside. In my case in my chest. A weird feeling and a little worrying when it happens. Can last from say 20-30 seconds, and sometimes quite a few minutes. At it's worst it is like I feel my heart beating ( a pulsating anyway from deep within my chest cavity), but beating/pulsating is so hard that I almost feel the pulse of every beat.A bit like that feeling you get when you a really scared or anxious. At first I thought I was having the beginnings of a heart attack, but obviously I was not! I have got it in bed, when resting in a chair and walking arond, so no set pattern as to what brings it on. I am thinking BFS related, and some others on this site have suggested that as well. I am hoping that is all it is...but who knows! cheersRodger