Chosen Solution

My phone keeps freezing and turning off and on and it calls people by its self.

could be a number of things including:

  1. issues with you OS. Did you just upgrade to 5.1?
  2. a bad connection inside the phone can cause that behavior. did you recently have a screen replaced? If so, the part might be bad or isn’t connected all the way causing random events. Do a hard reset (power button / up volume key held for 20 seconds) and see if that fixes it.

Did u have water on it Because that might be the case