Yesterday I happened to clinch my butt muscles and realized that I had a pain. When I got home I started feeling around. I found a small, hard bump, directly inside the anus. It's just smaller than a pea, I'd say.

I have no pain during bowel movements, no blood, just pain sometimes, and a bump.

What could this be? Is this a hemorrhoid?
And what can I do to get rid of it?