Iphone won't charge, no reason?

My iphone stopped charging. It's been in a life proof case since i got it, nothings happened to it. Just won't charge.tried two cables, two outlets, and my comp.still, nothing. Any ideas?
it's an iphone 4.

Try taking it to an apple store and charging it there. If still doesn't charge then ask for some assistance.

Looks like the battery may be bad and have to be replaced. Check online like Amazon and see if there's a battery replacement for the apple phone you have. Make sure the model numbers match.