Do you know how much you're worth? Do you get paid what you're worth? Unless you are an entrepreneur or at the very top of the company you work for, you may NEVER get paid your worth. Is that ok with you? If not, it's time for you to re-evaluate some things. Ask yourself, do I have a product or service that can be of some use to others? If the answer to that is no, are there classes out there that you can register for to help you get a raise in your current company?
The truth of the matter is, YOU have the power to decide what you will or will not accept. When you first applied for your job you knew how much the pay was going to be and you agreed to accept it. Depending on what your goals are now however or how your responsibilities may have increased, you may need to go back to the drawing board and re-evaluate what you will accept.
Try this tip:
Make a list of your responsibilities when you first started vs. what you are doing now.
Put a value on the extra work.
Present the increase of responsibilities and how the business has benefited from your efforts.
Express how much you appreciate the opportunity to work for your employer and propose an increase.
Please keep me posted on how this goes for you.