need help

Does anyone know how to find out their own national insurance number in the UK? :P I need it to apply for something and i can remember it. :P

Does anyone know what this could be or mean? Half way up my back i keep getting an area that goes really numb and sometimes is like pins n needles sometimes too. It happens random and has no pain with it, but always in the same area of my back. :P Has this ever been something anyone else has...