What Causes Pain In Finger After An Injury?

I hurt my right ring finger during flag football. I dont remember how it happened but probably during a collision. The range of motion in the finger is completely fine and pain free. However when i press on one side of the smallest knuckle (closest to nail), I experience some pain. Kind of feels as if there is a bruise on the bone itself. No real swelling to report though. It looks just like the corresponding finger on my left hand. I do feel it if i make a tight fist. Any idea if this means its fractured or bruised or jammed? It hurts right on the right on the edge of the bump on the side of the knuckle. Thanks!