Is slapping a shoulder and then shaking your shoulder, by a boss in the work place, considered assault? Can i bring a lawsuit for this?

I would need to know more facts.  Was you boss joking around or was he mad at you?  were there any witnesses?  Unwanted touching is assault/battery and is unlawful whether at work or on the street.  Were any marks made on your shoulders?  If yes, did you take pictures?  Is the office vig enough where you can report it to a human resources person or another boss?  You can file a lawsuit if we are talking about principal here and you believe that you can prove your case.  He said she said cases are not great, but people have won.  If you have a witness, then you have a great case, which should settle quietly.  You do not want a big public case as it could hurt your chances of getting hired at another job (i.e. fear of you suing the new boss).  I would consult with a lawyer to determine if that is the best move and whether you have a good case.  How much money is this worth should be the question, when considering the consequences and need to obtain a new job as this is not a case to retire on.  I recently got a women 10K for getting slapped on the butt at work by someone (employed by another company) that came into the store who was in charge of putting inventory on a shelf.