Player got stuck and cannot move even though there aren't obstacles

Sometime when i moved my player in a 2D level that i generated or drew using tile pallete my player got stuck and can't move even though there aren't any obstacles. i think that maybe the ground is accidentally bigger than it look a few pixel and that maybe the problem. I sometime also cannot move through a hole that big enogh. Sometime these problem appear somtime not. What happend? Why? How do i fix it?

I also heard of perfect pixel camera package. Will it help?

My game is pixel art.