HELP! Lock button

[TheNoobDroid]

Every time I lock my phone it turns off instead. If I leave it 'sleeping' for more than 5 seconds, it turns off so then I have to boot the phone.Not even at low battery percentage.

The phone is not rooted.

I tried:
Going to safe mode
Factory reset
Battery pull

 

[Iammisssam1]

Well just a day ago my phone started being weird. Like when ever i press the button to make my phone Go to the lock screen/"Sleep" it doesn't ever want to. I already took out my battery but when i put it back in it automally turns on. Which it never did that I always had to hold down the power button to turn it on and off. I don't know what to do!! Do i have to replace my phone? Please help i really do need help.