Why does my iPhone 6 turn on and back off several times?

Yesterday my phone was in between my bed and wall while i was watching tv (for about an hour). When i picked up my phone the apple logo was there, then the screen went black. The apple logo appeared again, then black again, did this at least 10 times. Then i got fed up with it and kept pressing and holding the power button over and over again. It finally turned all the way on. I thought that was the end but it did the same thing (even when i was using it) like 5 more times. I was supposed to wake up at 4:30am today so i set an alarm on my phone. Woke up at 7:30am to find my phone was doing it again. So it was probably doing it for at least 3 hours! I need this fixed can someone please help? Could it be water damage? UPDATE: i have updated from ios 10.1.1 to 10.2.1 which a few people said would work but its still doing the same thing.