Why is my BlackBerry Z10 getting overheated?

My blackberry Z10 is getting overheat within 1/2 hr. I'd make sure that my other apps should not run in background, I only use my phone at night to chat with my friends and I only use whats app but still my phone is getting heated within 1/2hr it gets vry hot, this problem has started occur frm past 3 nights . Is this a very severe problem ??? please suggest me some solutions to this problems ....

If your phone is overheating it could be something running in the background. even an app that is necessary to your phone. The best thing you can do is to reload the operating system and see if this helps it. And do not restore.