First make sure there is no trim pieces catching when opening or closing the door. Check on the inside and outside. Sometimes a center door moulding will start to peel up and catch on the fender. Also check the weatherstrip to make sure it is not sticking from freezing in this weather, it's cold here in PA not sure where you are.
If a visual inspection does not reveal a problem then open the door fully and lift it from the bottom edge. Feel for play in the door hinges or from the bolts being loose. Compare both sides to make it easier to feel a problem.
If after all of this there are no mechanical problems with the door and it is indeed caused by the striker not hitting the latch correctly then I can give you directions on how to make adjustments.
You can try a simple solution. Open the door completely and have someone hold it open while you are working near it... or be very careful not to bump it while you are working nearby. Right where the door is catching on the fender, try pulling the fender out slightly with your hand to gain some extra clearance.
It is possible somebody hit it with their leg in a busy shopping center parking lot or some similar situation. Be sure the door moulding is securely attatched. If it isn't you will need to remove it and clean the double sided tape from the door and then reinstall the moulding with new tape. You usually do not have to buy another moulding unless it has been damaged from rubbing too much.