After it froze, the apple watch won't pair. when I look for the app on my iPhone the list of devices is empty.

What model of phone is it and what version of ios is it running?

What model of watch is it and what version of WatchOS is it running?.

What troubleshooting steps have you tried?.

What errror messages are you receiving?.

Has this watch ever been paired to another phone?(Very important).

Did you unpair the watch from the old phone first like this;

nitzan224 wrote:

Should I erase the Apple Watch from my current account?

Yes because that will remove the activation lock and free the watch up to pair with your new phone,follow the steps that I posted earlier.

Have you tried restarting both the iPhone and the Apple Watch? And also check that Bluetooth is turned on on both.