iPhone6s screen stutter

Hello,

My iPhone 6s is exhibiting Screen stutter from time to time these days, even when (apparently) no Apps are running. By Stutter, I mean it becomes unresponsive to a touch, then moments later it acts upon that touch, and successive touches between then and now. The iPhone even appears to restart (though rather quickly).

Is there any way that I can investigate what processes are running on the iPhone ... something like a "Task Manager" or "top" command, perhaps even a dev tool, that I could use to connect to the iPhone from my Mac Mini ?

Thanks in advance,