Small hard lump/bump under skin of lower shin.

Ok so I recently noticed this and I haven't known how long this thing has been on my leg but on my lower shin on the near the left side is this really small hard bump. It's not a visually noticeable bump/lump but its raised enough to be felt, it's very low but raised. I don't have pain when I walk and I don't have pain on it ever so far that I noticed. it can't be moved around. The only pain I have with it is when I press on but mostly near it but not directly on the lump and it feels like I'm pressing on a bruise(like i have pain on the front part of the shin) . What could this be? It's pretty much under the skin