Lately I have been awakened at night by a fluttering sensation in my chest. It does not seem to be related to my heart beat, and there is no pain. It is of such a high frequency that I feel that I can almost hear it. It is a constant sensation almost like shivering from being in the cold. Also, though this may be unrelated, I have had vocal problems where my vocal cords seem not to want to vibrate. I am on Lipitor, Zestril and Ritalin.