touch screen is not working, so I cannot enter password to unlock phone

hold home button and power button at same time till iPhone powers off. then power back on. If persistent you may need a screen replacement or restore your phone in itunes.

Get that screen working first.

If the screen isn’t working on your iPhone or iPad - Apple Support

Were you able to determine if the screen is bad or the phone has just frozen?

Try hard reset:

Press volume up (+)

press volume down (-)

Hold power button until you see the Apple logo on the screen

Check if the touch is back.

If not, you better take it to an Apple Store or Authorized for a proper check and repair.