What Causes Sensitive Mole On Back?

I have a mole located on the right side of my back, that was sensitive when pressure was applied (like poking at it with my finger). I got injured a few years ago on that direct spot, now it s like a blood bubble, in the color of a mole... when pressed it stings like a needle prick. Even when getting dressed, when a shirt rubs up against it, it stings...