Thank you for the query.
Most likely you are facing with nothing more than hemorrhoid. Its the most common reason of a bump in the anus. It gives itching, can get painful when clot appears inside, blood on the surface of the stool can appear.
Other possible reason of such bum is anal fissure
(in such case it is called sentinel pile, strong pain when passing the stool appears), rectal abscess
I suggest you to visit general surgeon
and have rectal examination
If its a hemorrhoid you should try such treatment:
- avoid constipation
(increase fiber rich products and mineral water intake)
- wash your rectum after every stool
- do not push hard on stool
- have sitz baths with Quercus Cortex
- use hemorrhoids suppositories
Such treatment should help in a week or so. If not, surgery might be necessary.
Hope this will help.