Why am i constantly getting pink eye but only in my left eye?

? HSV: Could be recurrent herpes simplex virus (hsv) conjunctivitis. It tends to affect only 1 eye. This would be likely especially if you tend to get cold sores around the mouth/lips. Another possibility is floppy eyelid syndrome which can lead to recurrent redness typically on the same side that a person sleeps on. This tends to be more common in overweight people. Next time it's red see an eye md.