There are a few reasons why your PlayStation 4 controller might be vibrating constantly. One reason could be that the controller is not in the correct position. If your PlayStation 4 is in the stand-by mode, it will vibrate randomly until you move it to the active or standby mode. If your PlayStation 4 is connected to the network and you have an online game account, then your controller might also be vibrating because of how often your PS4 is checking for updates.
