Do you have fast charge enabled? Fast charge and USB data communications are mutually exclusive. When plugged into a computer open up the battery page in Settings, it should say USB or AC unless it's already fully charged.

Have you tried a different USB cable? Your cable could have broken data pins.

 

Yeah, there's this bad thing out there called USB CHARGING CABLES. They are for charging only. No data transfer... I ran into the same issue last week.

So don't throw out the cable, just use it for charging. Feel free to mark it with tape or something so you know which is which