Painful red bump located at the base of an eyelash or under or inside the eyelid, can be a stye (an acute infection of the oil glands of the eyelid).
The first symptoms of a sty are generally redness, tenderness, and pain in the affected area.
The eye may feel irritated or "scratchy", and you may feel discomfort during blinking of the eye, have watering of the eye, and sensitivity to light.