How fast are you drinking? Is it slowly, or just gulping it down? If you drink liquids to fast the muscles in your throat can contract and cramp up causing pain. Though because your feeling pain in a certain area (under your Adam's apple) it could be mild reflux or a small infection. I'd go see your doctor about it.
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Everyday I look into the mirror in my room and realize that I need a step stool. B> height ;_;