Hey there Armyflyer,
Thanks so much for using Apple Support Communities.
Are you experiencing any other issues with your Apple Watch, such as issues viewing apps in the App Store or viewing your surrounding area in Maps? The reason we ask is that it's possible your Apple Watch is experiencing a network issue that is causing it to be unable to access those Pandora stations directly from the device. If that is the case, you can try forgetting your local Wi-Fi network and then reconnecting to it to see if that may help. This article has the steps to both forget a network and reconnect to it: Connect Apple Watch to a Wi-Fi network - Apple Support
If you are able to load the App Store and Maps without any issues, then you may want to reach out to Pandora directly to see if they can offer additional assistance in troubleshooting their Apple Watch app. Here is where you can start with that: Pandora - Contact Support
We hope that this information is helpful.
Have a great day!