If your Galaxy S4 falls, and you start to face Samsung Galaxy S4 not charging- grey battery problem, next, take a pointed wooden toothpick, a magnifying glass and a strong light and see cautiously if any bar across the center of the charging port. Make sure it’s in the center and not curved to touch one of the sides of the shell. If you find that it is bent, afterwards straighten it using the toothpick point meticulously.