Have you recently dropped your iPhone 7? Even the slightest drop can cause the small cables that connect the logic board to your iPhone's display to come loose. If those cables were dislodged, it could be the reason why your iPhone 7 touch screen is not working. Sometimes, it's possible to reconnect them without having to open your iPhone.

How Do I Press Down On The Screen Directly Over Logic Board Connecting Cables?

Press down on the part of your iPhone's screen where the small cables connect to the logic board (use the image above as a guide if you need to).
Be careful not to press down on the display of your iPhone 7 too hard, as it could cause the screen to crack.