iphone 5s freezes up when textng

Hello Angie03,

Thanks for participating in the Apple Support Communities.

Try these steps first if your iPhone appears frozen when you send text messages:

Restart your device and check for updates

1. Restart your device.
   
2. Check for a carrier settings update.
   
3. Check for an iOS software update.

From:

If you can't send or receive messages on your iPhone, iPad, or iPod touch - Apple Support

Sincerely,

Jeremy