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.
Seeing the time frame I would assume that it is just a small infection. I would advise getting some rest also drinking some acidic drinks like lemon juice or orange juice should help. It'll burn at first but it helps kill bacteria in your throat also mixing a small amount of salt into your drinking water should help as well. I'd recommend that over using over the counter medication. I'd only see your doctor if this continues on for more than a week as it could be an early sign of mono ( I assume this because you said you had pain near your adams apple which is close to your lymph notes).