Touch Screen Not Responsive

i had a 6s Plus and the screen stopped responding to touch so i sold it off as parts because i concluded it was the Logic Board. I have been using my 5c for a back up for a week and it just now started not working. It was glitching out so i reset the phone and it worked and a hour later it just quit responding. Any Suggestions?

• I let it set for 30 minutes and it works again but any idea on what is going on?
• In further testing some apps don’t respond at all, app manager glitches out, sometimes login doesnt work, and home screen works 100%