Read about fascisculations and see if this is what you mean be skin shakes. These are very fine muscle tremors/twitches of sort that can happen anywhere on the body. Most people have experienced an eyelid twitching...this is sort of the same thing, but muscles in the legs, arms, etc.

http://en.wikipedia.org/wiki/Fasciculation

The heart pounding is more autonomic sounding. Did you actually experience this feeling WHILE the holter monitor was on, so they could see your heart's rhythm/rate at the time it was happening?? If not, then you may inquire about an event recorder for 30 days. This way you can push a button when it happens and it will record the activity at that time. Yes, everyone has some tachy rates at times, but it all depends on what you are doing to provoke it.

The lack of sweating can be autonomic...or medication induce (all depending on what you are taking---if anything).

Urination problems can also be autonomic, but typically it's more difficulty initiating urination and inability to completely empty bladder.

I don't know much at all about thyroid, so someone else needs to answer those questions. But if your TSH and other thyroid tests were normal, then I wouldn't worry about thyroid.