[doublepost=1505436397][/doublepost]Friend and I had the same problem with our 5s. It was a battery problem. Went to an an iPhone Fixit place and had the battery replaced.
Works good now.
But battery (old battery) swelling made the screen become detached.
They kind of glued it back together.
I am holding it together with a case.
Will be getting in iPhone 8 soon