The main reasons a phone keeps randomly vibrating are usually related to app notifications, system alerts, haptic feedback settings, or hardware issues. These random vibrations often happen due to:

• Incoming app notifications or background silent alerts that don't show visible messages.
• System alerts like low battery warnings, poor network signal, or software updates.
• Haptic feedback, such as keyboard vibrations or touch interactions if enabled.
• Malicious apps, malware, or apps downloaded from unprotected sources triggering vibrations.
• Hardware problems with the vibration motor itself causing rogue vibrations.
• Features like NFC interacting with cards and causing vibration on some phones.
• Accessibility settings or repeat notification alerts turned on.
• Hidden/system-level notifications like government emergency alerts or banking app background alerts.

To fix the issue, try these solutions step-by-step:

• Restart the phone to clear bugs and reset processes.
• Turn off vibrations in sound settings or disable haptic feedback.
• Close all open apps to stop background app vibrations.
• Turn off vibration for individual app notifications via settings.
• Disable repeat notification alerts if enabled.
• Disable NFC (especially if using wallet cases or credit cards on the back).
• Check notification history to identify hidden alerts.
• Scan the phone for malware or suspicious apps.
• If available, run a vibration motor test in developer or diagnostic mode.
• As a last resort, perform a factory reset after backing up data.
• If the problem persists, it’s likely a hardware issue needing repair.

These steps cover both the most common and some hidden or overlooked causes of random phone vibrations.