i cannot get my iwatch 7 to vibrate when i get a text

Hello,

Please check this suggestions:

Choose how apps send notifications

1. Open the Apple Watch app on your iPhone.
2. Tap My Watch, then tap Notifications.
3. Tap the app (for example, Messages), tap Custom, then choose an option. 

Change notification settings on Apple Watch – Apple Support (UK)

Adjust haptic intensity

You can adjust the strength of the haptics—or wrist taps—Apple Watch uses for notifications and alerts.

1. Open the Settings app  on your Apple Watch.
2. Tap Sounds & Haptics, then turn on Haptic Alerts.
3. Choose Default or Prominent.

Or, on your iPhone, open the Apple Watch app, tap My Watch, tap Sounds & Haptics, then choose Default or Prominent.

Adjust brightness, text size, sounds, and haptics on Apple Watch – Apple Support (UK)