I have a constant pulse under one eye lower lid, in time with my heart beats for the past two weeks. you can clearly see it pumping. what should i do?

Lid irritation: More often than not this is related to eyelid irritation. Use some artificial tears regularly, like 4 times a day and see how it does! if not better, see an ophthalmologist.

Other things: That is usually a symptom of dry eyes, stress, caffeine and rarely a sign of a problem with your neurologic system (brain and nerves) or an imbalance of electrolytes (blood chemistry). . Contact your treating eye doctor to work this up and make a proper diagnosis a d treatment.