Phone started getting hot spot on device

[VegemiteKid]

The patch appears to be where the SIM/memory card is, and it gets very hot to the touch. It has happened when the phone is idle and does not appear to happen when I am doing something to access that area (e.g. playing movies or making calls). It's hot enough to go through to the glass/screen side. Turning the device off and leaving it for 10 minutes lets it cool, and it doesn't happen again for a couple of days. The phone is around 1 year old, and has only started doing this in the last couple of weeks.

 

[B. Diddy]

When that happens, check your battery stats to see if any app seems to be using an excessive amount of battery.

A corrupt SD card can also cause behavior like that, because the system's Media Scanner can get hung up on a corrupt file, thus causing the CPU to work overtime. Unmount the card in Settings>Storage​, remove it, and reboot. See if the overheating recurs.