I work in a freezer at work. The roof leaks water then it freezes on the floor. I didn't notice the ice in my work area. I slipped and hurt my back.

Generally you can't sue your employer for pain and suffering from an injury that occurred at work, but there may be an exception or perhaps another defenant like a maintenance company or roofing company responsible for the roof, so you should consult with a good lawyer as soon as possible.