Sneezing a lot, nasal congestion, and only my right eye keeps watering. what is the cause?

Allergy: This is likely a case of allergic rhinitis. The fact that you have both nasal symptoms and eye symptoms is fairly common. it is likely due to environmental allergy. You could try an over the counter antihistamine and see if that helps you. Something like loratadine, or fexafenadine. I hope that helps.

Allergies: You probably have allergic reaction to something. Over the counter allergy medication may be of help.

Allergic: You likely have an allergic disorder although having only one eye involved is unusual. You can get an OTC antihistamine eye drop for the eyes and OTC nasal steroid for your nose. If neither worked well enough, consult an allergist. Antihistamine may reduce the sneezing but not the congestion which can only be controlled with a decongestant.