Unilateral redness upon working/stress, assiciated with swelling of one eye! I suppose that there is no irritation, itching, discharge etc... meaning No infection Is it a lid swelling which is only one sided? Is your eye otherwise normal apart from working hours? Is it the lid or conjunctiva which appears red? Does the swelling increase when you bend your head to toe level  within few minutes? One of the cause could be hemangioma which should be observed if the symptoms are not increasing; else it should be excised or electrocoagulated if its increasing. You need to be examined by an ophthalmologist to come to a clear cut diagnosis Hope this helps :)