iPhone freezing and turning off repeatedly

So this just started today.I woke up with my phone dead and quickly put it on the charger.Then while I was using it for sometime it froze so I decided to lock it and when I tried to open it ,it was already off.So this is now happening continuously.If I put it down and it locks same thing happens over and over again.

[Re-Titled by Moderator]

Original Title: Glitching