Why won't the apps close in the background?

My phone has a few times where it will overheat and freeze up no matter where it is at. There were a few times where it would start back up on its own, and there were other times where I had to restart it myself. For some reason, when I had to restart it while using Google and Google Chrome, it won't close out of the background. I've disabled it, forced stop, and even uninstalled the apps but nothing has helped. Is there anything more I can do to fix it? They are a serious nuisance and I would really appreciate getting this problem solved. Thank you.