My iphone 6 shut off and will not turn on?

I've had it for around a year and I've dropped it a hand full of times resulting in one crack. I've went through a few chargers so many the problem is something to do with the battery? It was around 60 percent when it randomly shut off. Even if it had died, the dead battery warning would show up whereas when I hold down the power button it stays a black screen. I also have a lot of videos, photos, and music videos on my phone. My phone constantly tells me it is not backed up. Considering my lack of storage, I don't update it often. This has happened once before but it came back on within an hour. Today it shut off no later than 1 pm, it still has not turned back on (11:00 pm). Has this happened to anyone else? Should i just take it to a phone store?

Have it repaired

Try this.

(make sure it has been "charged" prior to this)

hold down both buttons (home and off button)

hold it for 10 seconds.

now, release the off button, (while you are still holding the home button)

hold the remaining home button for 10 seconds.

Then release the home button (by now nothing should be held down)

Your iphone sucks then