iPhone randomly vibrating without notifications

Hi Bdogo6,

There may be something that is causing the vibration to go off that is software related. Updating the software installs the latest protections and bug fixes. This can be done by backing up and then updating the iOS. To complete both steps, follow this:

1. Back up your device using iCloud or your computer.

2. Plug your device into power and connect to the internet with Wi-Fi.

3. Go to Settings > General, then tap Software Update.

4. If you see more than one software update option available, choose the one that you want to install.

5. Tap Install Now. If you see Download and Install instead, tap it to download the update, enter your passcode, then tap Install Now. If you don't know your passcode, learn what to do.

Update your iPhone or iPad - Apple Support

If that doesn't resolve this, verify all apps are updated. There may be an app that is causing your iPhone to randomly vibrate. After iOS updates are released, often app developers will release updates for their apps. To update apps, follow these steps:

1. Open the App Store.

2. Tap your profile icon at the top of the screen.

3. Scroll to see pending updates and release notes. Tap Update next to an app to update only that app, or tap Update All.

How to manually update apps on your Apple device - Apple Support

Cheers.

If you have Pokémon Go installed, that is the culprit.

See the answer from stedman1 here -

iPhone Vibration - Apple Community