Is the Apple Watch o a cellular plan? Then you can get text messages without having to pair it to your iPhone. In order to pair it try this
If you can't unpair Apple Watch because you don't have its paired iPhone, you can erase the watch.
When you erase Apple Watch instead of unpairing it, the watch is still protected by Activation Lock. Before you can pair Apple Watch again, enter the Apple ID and password that was used to set it up.
- Open the Settings app on your watch, then tap General > Reset.
- Tap Erase All Content and Settings, then tap again to confirm.
- Wait for the watch to unpair.
- After Apple Watch unpairs completely, you can pair again. You'll need the Apple ID and password that were used to set up the watch.
See this link for further reference
If you can't pair an Apple Watch with your iPhone - Apple Support