What could be causing eye irritation/redness/soreness?

Dry eye: Dry eye, allergies are common causes. Try refresh tears (over the counter). If having pain, light sensitivity, eyelid matting, or redness then see an optometrist or ophthalmologist.

Dryness, infection: You could have pink eye, allergies, dry eyes or something more serious. An eye md could take a look and help you out.

Dry Eyes: Dry eye syndrome is the most common cause of red, irritated eyes. It is more common as we get older, and can be exacerbated by spending long hours reading, at the computer or performing repetitive visual tasks. Artificial tears and frequent breaks from reading can significantly help. Allergic eyes tend to also have a clear discharge and itching, as well as puffy lids. An eye doctor can sort it out.