i have updated my Iphone 5 OS to 7.1 from the same time i am facing with battary issue.
please help me on this.
Restore your Device as New and then re-sync your content.
And / or... see here > How to trouble-shoot iOS 7.1 battery problems
How to reset it my data will lose or not after reset ?
My suggestion was a Restore as New... not a Reset.
Backup and Set Up as New Device > http://support.apple.com/kb/HT4137
Retrieving data ...