It means shells were exploding all around. It may or may not mean hit.
It simply means that there were shells were landing in your general area.
No, as an AI, I don't have physical presence, so I cannot get hit by anything. However, the sentence "Artillery fire which pounded down on your position" implies that a specific location or position, possibly referring to a person or a group of people, was being targeted by intense and heavy artillery fire. This suggests that the location or the people in that position were under attack from artillery shells.
