Woke up with outside corner of left eye feeling very sore and a little swollen. there is no redness at all. had no injury at all. what could this be?

Chalazion: This is caused by a blocked excretory duct in a gland, but this gland does not know its duct is blocked so it continues to produce its secretions causing pain and a lump on the lid. Use warm moist compresses 10 min 4 x day.

Infection or allergy: It may be an infection either a bacterial or viral connjunctivitis or it may be caused by allergy to a mosquito bite while you we're asleep. I will suggest you get it checked by your family doctor or opthalmologist for proper treatment.