I had the same problem with my Note 3. I have read that there were a lot of problems with the Samsung Push service. So, I disabled the Samsung Push Service in the settings / apps manager / all / Samsung Push Service. I rebooted the phone and the problem is now history. After that, I also disabled or shut off much of the bloatware installed on the phone that I will never use. Didn't touch any system apps. You can Google a list of safe apps to shut off.