Q: I have an iPhone 4s 16 gb with 7.1.1 and when I use the 2g/3g service (no wifi) the phone from behind gets very hot. also the battery life is too short

Hello Hiteshk0007,

Thanks for the question. The following resource provides some information about temperature:

iOS devices: Keeping device within acceptable operating temperatures

http://support.apple.com/kb/HT2101

When using the device or charging the battery, it is normal for it to get warm. The exterior of the device functions as a cooling surface that transfers heat from inside the device to the cooler air outside.

By all means, if you believe the temperature is a concern (along with the battery life), you can isolate the issue by restoring your device as new:

iOS: How to back up your data and set up your device as a new device

http://support.apple.com/kb/HT4137

Thanks,

Matt M.