So I've had this 4S which I bought from a friend in February and he got it from apple via warranty replacement in November '13. Flawless phone too Worked perfectly until just 4 days ago. Now for some reason the battery drains from 100% to 10% in 4 hours on sleep mode and the phone is constantly super hot. I've tried turning off all background refresh and even restored the phone. I've recently moved to a new area for school and I'm now roaming on T-mobile, AT&T antenna now. That's been fine for 2 weeks before this happened so that can't be the problem... Anyone else get this problem before?