Hi I also have internal shakiness but I call it electricity. Not sure if we have the same symptom. I have it in my legs (calves) bad and over the last few years in my hands. It gets much worse if I don't sleep well. I also need pain killers for it as the vibrations don't stop and the shakiness is also painful after I start feeling it for 5 minutes. Nothing else has helped me. I am also hypothyroid. It was also spreading to the bottom of my lumbar. I had that for a week and I did read on line that there is not enough calcium in your body and the nerves are not connecting and can cause this tremor. This person recommended taking Tums - since I was desperate for it not to be in another spot in my body I did take Tums , the first 2 weeks every day just 2 or 3 at the most. And believe it or not that stopped the vibrations in my lower back. Who knows? I now take Tums about 3 or 4 times a week to make sure, if they are helping to stop this weird electricity, that I have enough calcium in my system. Maybe it is part of a calcium issue? NO dr. in 20 years has any idea why this happened but it happened to me at the exact same time my thyroid went. I am sorry that this is going on at only 28, but maybe the Tums might help you.