Q: iPhone screen&home button responding intermittently

hi all,

my phone has developed a fault over the last few days where it sometimes doesn't reaping to touches on the screen or presses on the home button for 10-20 seconds but then does the 10 presses you try to make all together after the delay. It's an iPhone 6s Plus running 9.3.5 and haven't changed anything recently.

JUst oust wondering if anyone has experienced this/knows how to fix it before I return it to the shop for repair.

thanks