How can I get my back pay?

Mangers are sometimes but not always exempt from overtime pay. I can't tell you how many times employees would be better off being paid hourly than salaried. Many times an employee only realizes that when they land another job or leave. I assume they pay you a salary. Hopefully you have the discretion and independent judgment needed to be salary exempt. What that means is that if you are called a manager but don't have the discretion and independent judgment to be salary exempt then you are not. With a decent employment lawyer you might in that case be able to argue that you should have been paid hourly, you were not exempt, and you want to go back up to 6 years, ask for liquidated damages, and have your employer pay your own attorneys' fees when you win at trial. They are good cases but rarely easy or fast. You are apparently non union, you do not work for the government nor did you enter an employment contract, an agreement usually signed by an employee and their employer for a specific term (i.e. one year contract). If none of these apply you are probably "at will". What that means is that your private employer can lie to you. But they can not discriminate against you. Sometimes an employee thinks they were discriminated and when an employment lawyer speaks with them it turns out they are owed unpaid overtime. They were improperly classified as managers and should have been paid hourly plus overtime. In your case it might be that you were discriminated for some protected  class to which you belong and that might be your strongest claim. Or you might just quietly confidentially look for another job and leave a dishonest employer once you find a better one. Dishonesty itself is not illegal. Dishonesty in selling a product or negotiating a goods contract might be. But in employment as long as an employee is paid at least minimum wage plus overtime thats often OK. Unless the employee is misled into believing they are an assistant manager when they have no authority to hire or fire, don't make policies and the list goes on. In that case even a $90,000 a year manager might be entitled to unpaid overtime. Why? Because their salary pay stubs misrepresented the implied discrtion and independent judgment they were supposed to have. Make someone a manager they better have the discretion and independent judgment which goes with that title. It is shocking how many employees never realized they were being discriminated. But proving that takes time and good strong facts. Call some employment lawyers because I can read that if you complain too much without having a backup plan of potential litigation you could lose your job and maybe even unemployment benefits.