This page is under construction. The details should be pretty good, but the presentation might need some work.
Hobgoblin warforged seems the most likely at the moment. Apparently the hobgoblins have discovered ancient “archives” (repositories) of dormant warforged underneath some of their settlements, which they have been studying for some time. They had not discovered how to wake them up. But then they were suddenly and accidentally awakened by a giant wild magic surge from the collapsing Kintsugi Tower.
Most of the warforged were quickly recruited into the army of Vendetta, who believes the hobgoblins and orcs of the Stalwart Shield slew the god of the warforged and then enslaved them. She wants to wipe out the Shield and is currently in control of the Shield's capital.
Your warforged would either be one that initially joined Vendetta's army and then quit for some reason, or could have been among the few warforged that she was unable to reach. Either way, you would retain the abilities you gained in the ancient days when you were originally alive, but you would have no memories of that time—as far as you know, your life started with the surge from the tower, locked in a dark, morgue-like compartment inside the archive where you were being stored. Either the archive was in disrepair and you were able to wander out on your own, or someone came along and released you.
In terms of personality, you would awaken with whatever personality you had in the ancient past. However, it has been discovered that some of the warforged come back a little… glitchy. So basically you're free to make up whatever you want. You may even give yourself an imagined past which you are convinced is real.
Most of the hobgoblin warforged resemble hobgoblins at least a little bit—the general shape of their faces, some engravings in their heads that stylistically represent hobgoblin features, etc. But that's not totally necessary if you're not into that. You could be a different design—a prototype, perhaps, or a warforged that was made in the ancient past as a gift to another race.
The Shield are only a few days' journey to the west of Brightshore. It would not have been difficult for you to wander aimlessly until you found the town. But it's also possible someone told you about the town and pointed you in that direction.