The game is tile based and you can only interact with tiles that are in a strait line with your player.
I made a little graphic to explain it:
From your current position, you could interact with the red colored squares.
But while looking at the range inside the black lines, you are going to interact with the item directly infront of you even though it looks like you are looking at the other items.
So to interact wit the other two Pokéballs, you have to move a step to the left/right.