Your termination was of course a pretext. You were assaulted by him and he was angry you had the temerity to attempt to file an injury claim. Work through your Union for a wrongful discharge grievance.

Or I should ask, does your contract state you can not be fired without cause??

If it does not, then it is time to consult a private attorney.

Your boss makes me sick to my stomach and I don't even know him.