my phone froze over night (i have a galaxy s7) and is on a black screen I woke up and my screen is black but the green charged led is on and my phone is no longer plugged in. I've tried multiple things to fix it such as holding the power button, holding volume up and the home and power, I've let it sit for an hour off the charger, I've tried to connect it to google play.... i'm not sure what I should do any help would be appreciated.
Have you tried recovery mode? Usually, volume down and the power button will boot you into recovery. Other than that, there's plenty of ways to reboot your phone with adb. adb shell reboot -p 

Adb shell reboot-p  


will set you straight I believe

Edit: this will only work in the case of a frozen phone. If its off and won't turn on at all, and recovery mode won't work, it may be hardware related