What Causes Dark Spots On All Over Body?

All of a sudden I am starting have dark spots appearing on my body. Sort of like dark pigmentation. I am black, but the spots are very visible; on my back, arms, legs, and looks like little blood clotted spots on the underside of my fingers. Tiny dark shadow-like spots appearing on the soles of my feet, and little black moles starting to appear on my body as well. Male 5'7", 221 lbs., Also I was told by my Dr. my iron & vitamin D level are low, early part of last year.