Go to the optometrist, it'll probably be cheaper than an ophthalmologist. You could even go to a mall/Lenscrafters optometrist. If you have medical insurance they'll charge you the specialist copay on your insurance card, even if you don't have vision insurance. The office I work at charges, $60 out of pocket for these types of visits and usually provides free samples of antibiotics if needed. It's probably nothing, but could be something. Let a doctor look at it, you only have one set of eyes.