Am using Google lg nexus 4 and software version is 5.0.1. 4 days ago I switched off my mobile and put charging for 2 hours then I removed charging, turned on my phone and used 3 hours , suddenly my phone soft keys (i.e back, home & recent) didn't response, I thought that my phone was hang. So restarted my device, but still my soft keys touch wasn't working, so I switched off my mobile for 2 hours, after turn on my mobile that touch wasn't working, so I decided to format my device, after reset my device same problem I had faced. I can't understand why my soft keys are not working. Please help me what to do.....