thanks for the infortmation.
There are a number of conditions that cause the symptoms you describe. Sinus infections commonly cause your symptoms, although you dont list any other symptoms related to sinus problems such as stuffy/runny nose, mucous, ect. Glaucoma is a possibility. Periorbital cellulitis, an eye infection could be another possibility, although your doctor would have noticed this because the condition causes inflammation/redness of the eye.
I must add however that you should never self-diagnose any medical condition you may have. You should see a doctor for diagnosis.