C.S.
molars are not fun for the kids when they come in as you can guess..they are probably hurting him. If you are comfortable you could give him some tylenol to help with the pain but you probably already know that!
Because of his age he doesn't understand or know how to let you know he is uncomfortable and the "bad" behavior could be his way of trying to get it out...or it could just be typical 2 year old behavior of just learning new boundries etc.