the Apple logo keeps flashing

This has been happening for the last few days already even tho my iPhone is rather new. A few days ago, my iPhone would not react, it just was a black screen so I did a hard reset and then it worked fine again. Now yesterday I was browsing an app then suddenly my iPhone showed the apple logo with the white background for a few seconds then I landed on my lock screen and it happened today again. What's happening? And how can I "repair" it?