I suffer with anxiety, and I too often get the feeling that a little bug is crawling around my chest. It feels like a slight vibration or pulse; it doesn't hurt but it is disturbing because I don't know whats going on inside to cause it.
mj is right, these suggest something. In the meantime, you can add magnesium citrate as a supplement and see if it helps -- you might not be getting enough in your diet or getting too much calcium, and magnesium is responsible for relaxing our muscles.
These can be symptoms of anxiety; however, if you are having no other symptoms of anxiety, it might be a good idea to have some blood work done (if you haven't already). Did the neurologist refer you to a psychiatrist?