Do you have an Exchange email account configured on your iPhone?
If your Usage and Standby times are identical, this is a symptom of either a software issue where a restore normally fixes it or an issue with an Exchange server loop where the Exchange server is not allowing the iPhone to go to sleep. If you do have Exchange, try turning off Exchange for about an hour, then turning it back on. Then monitor it from there. If the issue persists, you may need to restore as new.