As you didn't root or install any custom Rom, this leaves one the apps you've installed as a possible cause. If you contacted Samsung support, they probably would recommend a factory-reset to rule out software issues as well, so this is a working approach.
Yes, a factory-reset would delete all data and the apps you've installed. You might wish to take a look at our factory-reset tag-wiki and its most frequented questions for details. If a factory-reset indeed solves your issue, start re-installing your apps one-by-one with enough time to check in between.
See also our backuptag-wiki for hints on how to save your data. Helium - App Sync and Backup might come in handy here, as it allows you to backup apps and their data, and even restore them separately (one-by-one) in an easy way.
Of course, if you can live with the current state a little longer, you might want to wait for alternative answers first, so maybe a factory-reset is avoidable after all. If you want to use this approach, you find an appropriate item in your device's settings, as well as in the recovery menu. Again, you'll find more dtails via the mentioned tag-wiki.