This morning I received the new iPhone 5S I restored the phone via iCloud backup and reinstalled my apps. It took me 30-40 minutes. Brand new iPhone 5S overheated and battery was dropped down to 40% . I closed all the apps that were open, locked it, and did put it in to charge. When the battery was at 100% I started using my phone again but same thing happened again, phone was overheated and battery was also down to 40% in 30 minutes. Any reason why this happened?