What if when I find my product, I get the same compound as I did in my reactant? For example, FeCl3 + HCl ->FeCl3 + HCl.

Question

Then something is wrong. In this case, FeCl3 and HCl usually don't react. In very concentrated solutions of HCl, the FeCl4^- or FeCl6^-3 ion can form. In normal circumstances we would write NR after the arrow to indicate there was no reaction.