I work in a library and took a pay cut in 2008 when the state made budget cuts. Since then I have not had any raises. Is that legal?

Recently the younger employees have been given pay raises, however the few of us older employees haven't gotten any. They claim its because we are at the top of our pay scale. After taking a pay cut in 2008 and almost 7 years later I am making what I did in 2006. I can't leave because I have a retirement to consider. I almost feel as though this is age discrimination because they know I will stay to keep my pension. I have taken on more responsibility along with the pay cut because staff size has decreased. I am afraid to push the point too much out of fear of loosing my pension. I am not a librarian, but a clerk who also works in technical services.