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.

