iPhone wont charge

My iPhone 4s that I got a little over one month ago is already having serious charging problems, and there have been few to no drops, all with its case fully protecting it.

I bought a brand new wall charger and once I plugged it in, it stopped taking a charge from any device. I had to completely restore the iPhone, and then 2 days later charged it again and it died, but I could to a system reboot and it worked, but still will not work on the wall charger from and socket in my house.

Could the wall charger be infecting my iPod or is it possible that my USB socket in my phone was built defective, and if I have Apple Care through Sprint, could it be replaced?

Thanks,

njm