Unfortunately you appear to have a lemon. My first Droid either rebooted spontaneously several times a day or simply froze up requiring that I pull and reinsert the battery to get it going again. I took it back to Verizon after a few days of this and they replaced it. I have had no problems since. My wife did not experience any problems with her Droid. The forums and bulletin boards have numerous references to this type of problem. The solution always is to return the phone for a new one. Don't torture yourself. Take your lemon back to Verizon.
If you go into settings, sound and display,then scroll down to haptic feedback and leave the selection blank you eliminate the slight shake.
See if that helps.
During a call the screen will go dark. There is a sensor at the top that prevents cheek dialing. When you pull the phone away, it should light up. However, your phone may have gone to sleep. Press the power/wake up button and you should be fine.
If it is freezing (not waking up when you touch the power button) you may have an issue.
That shaking is the haptic feed back. You can turn it off in settings.