I have used my iPhone 5 for over 5 months with no problem. Recently, the phone sometimes gets very hot in its case while off. When I pick it up, not only is it hot, but the battery meter has drained down to a low level such as 15%. I notice that when the phone is hot, if I re-boot by shutting it down, it returns to normal. It cools-down and can be charged. This problem is intermittent but I am afraid the phone might catch on fire or even explode. Any advice? If I bring it for repairs, it will probably register normal. If the battery is defective, as it doesn't seem to hold a charge long, I will lose all data although I've done a back-up and a synch on my PC.