power button wont work and phone reboots itself when It shuts down

[kw21]

power button wont work and I tried to make it totally lowbat but then when I charged it, it reboots itself without me pressing any buttons. HELP PLS

 

[Hexa spring 8]

I may be wrong but from what I'm guessing is when you turn the phone off the power button gets stuck and when it's stuck it turns the phone back on the power button stays stuck just long enough for it to come back on for you to push the button again and hold it and then shut it down again and stays stuck just long enough for it to restart your phone try to investigate that power button a little bit more they have some finger juice around it that's causing it to get stuck on you push down and see if it comes right back up if not take a Q-tip with some rubbing alcohol and strain it out real good and lightly wipe around the area