I Have A Small Lump On My Butt Cheek. It

I have a small lump on my butt cheek. It is a little red but other than that not very noticeable but is hard to the touch and probably about pea sized. It is only bothering me when I sit or when I press on it. Is this just a pimple or something more serious? It does not have a white head or anything like that, but seems bigger than your average pimple.