Ipod touch 5th gen frozen screen and unresponsive assistive touch

So i have this problem lately where I use the multitasking button of the assistive touch (since my home button is not working) to kill apps then my phone will lag and become unresponsive. There's one time where the last app i opened was instagram and no matter what buttons i pushed-- assistive touch, camera and all, the screen wouldn't budge and just stay in instagram. I usually let the batteru drain so it can restart and all. Is this a hardware problem? Battery problem?