Welcome to Android Central! Which phone? Look in the Settings>Battery menu--are there any apps that are using an unusually high percentage of battery? Another common cause for overheating is a corrupt media file on the microSD card. If you have a card inserted, unmount it in Settings>Storage, remove it, and insert it into your computer. Then run chkdsdk to look for bad sectors: http://forums.androidcentral.com/am...guide-using-chkdsk-fix-corrupted-sd-card.html