i'm experiencing a short stinging/stabbing pain in the inner corner of the eye (near the nose). the pain comes and goes very quickly (the pain occurs and lasts for about 1 second) every few hours, but it's been 4 days and hasn't seem to improved, though it hasn't worsened. i haven't experienced any other symptoms. i've seen my doctor and he examined the eye but did not find anything unusual. meanwhile i'm still experiencing the pain every few hours. what could this be?