Answer: Your “market value” is determined by what someone else will actually pay you. If you can get a better offer, your current employer might decide to match it. But if jobs in your field are in short supply, then you have little leverage to demand more money.
With a company-wide pay freeze in place,would need a really good reason to make an exception for you. Without strong justification, giving you a raise would simply look like favoritism. And continuing to ask for one will only make you appear self-centered.