hemorrhoid

I'm 16 and just found out today that I have a hemorrhoid when I was trying to find out why my anus was itching, and when I had to do a number 2 it would cause painful discomfort and would bleed. I'm going to ask my mom about it and see if I can go to a doctors, but does anyone know why I have one? I wash down their all the time, shower everyday, and I'm a very hygienic person so if it's caused by some type of dirtiness or germs then I don't think it could be that...