I'm not sure which iphone i won, i believe it's a 4 or 3g, but i have tried multiple chargers on it, and nothing. The battery is there, i have tried resetting it. Also, it's dying faster then usual. I haven't dropped it or done any water damage. Yes all the tabs are closed and the brightness is low like always. I think something is seriously wrong with my phone, it only took two minutes for it to go down by 20 percent with it on and nobody on it. I can't afford a new phone and i dont have a contract so i cannot get another one.

Well it sounds like your battery is failing which since it's a Li-Po it will in time no mater what. Now for the bad news this battery chemistry might ether expand immensely or burst into a lithium fire. Luckely it is fairly cheap to fix with a kit that includes all the parts and odd tools being about 20$US + shipping all you need to do is determine what model it is.