Hi guys I had a very weird thing happen last night to my Lumia 920, well not that weird but still alarming. I woke up in the middle of the night and while my phone was charging the back of it was very very warm, almost to the fact that I wanted to disconnect the phone from the charger and thought it was not normal and I even did a soft reset because I was somewhat worried. Has this happened to any of you guys before. I know some heat may be normal but this seemed like an excessive amount and it seemed that only the top half was very warm.....very strange......I'll keep monitoring and if this persists do you think I should request a replacement from Nokia.
Maybe some app or process was working in the behind, and while charging it can produce a bit of a heat, and just as u told, in the upper half. IMHO, nothing to be worried about, but make sure u kill all the apps from BG before putting it on charge.