There are a few reasons why your body might vibrate in the middle of the night. One possibility is that you're experiencing hypnagogic jerks, which are brief muscle spasms that can happen when you're falling asleep.
Another possibility is that you have sleep apnea, a condition that causes you to stop breathing for brief periods of time during sleep. This can cause your body to jerk or vibrate as it tries to get you to resume breathing.
If you're not sure what's causing your body to vibrate, it's a good idea to talk to your doctor. They can help you rule out any underlying health conditions and determine the best way to help you get a good night's sleep.