Confirmed that turning off location services solves issue.
Background:
I've had the same issue--- intermittent unresponsive touch screen and sometimes false touch/random selection of things on screen. Happens ALL the time and was incredibly frustrated
Apple techs had no idea what was going on--- clear they were guessing
I initially thought it was a hardware issue (shaking sometimes resolved it). I switched the phone out at Apple Store (which involved restoring from backup) and upon inserting my old SIM card into new phone (at Apple Store) issue returned.
So I returned to switch out sim. Issue still going on.
Did 3 hard wipes of phone. Restored from cloud and ITunes. Issue persisted.
Today, turned off location services and no issue. No idea which app but a great relief.