Ridges/ribs on shaft sides

I've got 4-6 ridges, roughly 2-3mm in thickness, that run from the top to the underneath of the shaft on both sides. I've had them for years, probably caused by death gripping in my teens, and they don't cause pain but I think they have restricted my length by about 3/4 inch. Is it likely to be fibrosis, and should pe work be avoided if so?