Why does my iPhone 5s battery die so quickly?

Probably apps running in the background are causing this, sometimes Mail get's stuck connecting to the mail server, or some social media app like Facebook can also be a reason for prolonged background activity.

Try to reset the phone by holding the sleep and home button for about 10sec, until the Apple logo comes back again. You will not lose any data by resetting, but it can cure some glitches.

If this does not help, setting it up as new device would be the next step:

How to erase your iOS device and then set it up as a new device or restore it from backups

Maybe also take a look at this page about battery drainage

You may have a bad/defective battery. Make a Genius Bar reservation at your local Apple Store (if you have access to one) to have it evaluated for free. Free replacement of the battery may be covered if you're still under warranty.

https://www.apple.com/retail/geniusbar/

Also, Apple does have a battery recall in effect for the iPhone 5 (I'm not sure if this applies to the 5s as well). Check if your phone is covered by the recall at the following page:

https://www.apple.com/support/iphone5-battery/

I have an issue with my 5s's front display lifting up from the phone's body at the top-left. This is usually attributed to a defective/bloating battery & I myself have a Genius Bar reservation to pinpoint the issue. I checked to see if my 5s is covered under the recall but it is not...but it could still be a defective/bloating battery covered under the standard warranty. The phone is only 4 months old.

You should contact Apple Support about the battery message and see if they can clear this up. They can also test your battery online, in case you decide to have your battery replaced.

No, not as long as your device is still under warranty. Probably a glitch in the database for battery replacements, but be sure to mention that when you are calling them or getting your phone getting checked.

You're welcome, Good Luck 🙂

You don't have to be under the battery recall program to have a defective battery and have it exchanged under warranty.

I see you will be taking it in for an exchange but it's not the battery that's at fault...good luck to you. Apple will fix you up.

BTW, my issue was not a bad/bloated battery but rather the screen lifting was due to screen delamination at the top-right corner. The Apple Store would've changed the screen (supposedly) but to do so requires some type of calibration of the screen. Something on Apple's end for the calibration procedure was down, and had been down for a few days (nationwide I was told) so it was not possible to be done. I was given a replacement phone on the spot so all has turned out well. I now need to keep my eye on the wife's 5s for the delamination as well since they were both purchased at the same time.