Lately my eyes have been burning like they have a sunburn underneath my eyelids. what does this mean?

Probable dry eyes: Assuming that no other injury or infection has occurred, the most common cause of your irritation is dry eyes. Dry eyes can occur at any age, but tend to worsen as we get older. Treatment should begin with a thorough eye examination, followed by artificial tears 4 times per day. If you do not notice a significant improvement quickly, have your eye doctor re-evaluate your treatment options.

Dry eyes: Most likely it is dry eye related, but a thorough exam from your eye care provider will help determine the causes, and point toward treatments. In addition to artifical tears, omega 3 fatty acid supplements in the form of fish oil or flax seed oil can be helpful.