When you get hurt at work, the last thing you want to have to deal with is a dispute with your boss over the amount of compensation you should receive or if your injury should be covered by workplace insurance at all. Workers' compensation is designed to help you when you're hurt, and your employer should be willing to help you file your claim for compensation as long as your injury took place on the job.
Sometimes, there could be issues with the compensability of your claim. For instance, if you were on your way to work when you were hit, does that count under workers' compensation? If you got sick at work, was that illness caused by work, stress on the job or hazards you were exposed to? If it's a complicated situation, the claim may be debated and even denied completely.