At night, when laying down, my tongue will go numb and have burning sensation for a few seconds then go away...what causes that?

Good question: There is no easy answer for this, as there is too little information available. Your tongue going numb and burning is not normal, and could have several causes. Please see a dentist, oral surgeon, ENT (ear nose throat) physician and/or nurologist to have your tongue and associated tissues, including the nerves, examined. Only with the whole picture will someone be able to help you.