It's a system RAM issue. The phone allows a paltry 357 MB for apps to use in system memory.
The easiest way to clear this up is to back up to your home screen, hit the Multitask button (the third button, under the A in Kyocera), and swipe away all the apps. It's a good idea to do this after you've been using a lot of apps. It wouldn't hurt to reboot the phone every few days by powering it off, then turning it back on. Just don't do that as a hard reset (hold down the power button until it reboots) unless the phone really is frozen in time.
If your phone does freeze up a lot, you'll have to figure out which apps are causing it, then find lighter alternatives to use (apps that take up less space, and can install to SD if possible). For me, one of them was the Facebook app for Android. I uninstalled that and installed something called Facebook Lite. It runs as a mini web browser that links directly to a tablet version of Facebook.
I got my phone back in December as well, and have had it rooted for the past month. Rooting it allows me to use Titanium Backup, which lets me backup the phone, and freeze/uninstall system apps. I haven't uninstalled any system stuff though, just frozen (disabled) the ones I don't want running, which improves on the system RAM issue.
Uninstallling unwanted system apps does give you more system RAM, but that's risky. One person experienced boot loops by doing just that, esp. after Kyocera issued a system update earlier in February.
I also did the egl tweak (rooted), which frees the phone from running the software video drivers. That tweak alone speeds up the phone a good deal.
I hope this long post gives you some ideas to fix your problem.