I've only heard of that happening from childbirth or a disease like PID or endometriosis, not from injury.
From what I read online, if you are experiencing pain with a retroverted uterus it can signal a more serious reproductive tract disease. Your doc offer any treatment or test you for anything else?
There are treatments available to fix it. As for the workers comp, I can't help you. It really does sound (from my amateur research, I'm no expert on the subject) that getting it from an injury like that is rare, so I can see how it would be hard to prove. Perhaps seek the advice of another doc, and make sure you are tested for PID and endometriosis, and any other std's or non-std infections that you think are possible.
Sorry, I hope someone has better advice for you!!