Bump on adult ball python

http://dbpclan.net/bump.jpg


Well, i just noticed this bump while cleaning the cage today. Its hard, same type of hard as the bones. I notice no reaction or any indication of pain when putting pressure on the bump. (on the other hand, my snake is incredibly calm. 6 years old, never bit anyone incl. me) I know a snake will soak in its water dish if it has mites or w.e, my snake does not do that. It has had a change in behavior though, from in its hide all the time to laying on top of it chilling there all day.

I've noticed slight aggression increase, though never any bites or strikes.

I think i have given as much background information as i can. I will keep an eye on this, it just caught my attention a few minutes ago. Sorry for the cell phone picture, its my only means of snapping a picture. Notice, the bump is on its side. Think of this as an overhead view of the snake.

Need a better pic