My work will fire me if I talk about pay.

Exactly what the title says. I was required to sign a document saying that salaries are confidential and that they are not to be discussed. They gave me a promotion to now be my bosses boss and they refuse to give me any form of compensation for it. Not even fringe benefits. If I share my pay with others and get fired. Is the lawsuit really worth it? It’s a right to work state.