For no apparent reason, the index finger on my right hand has become swollen and is very painful. It has a constant aching feeling in it, and hurts really bad when I apply any pressure. If I sit still for awhile and do not move my finger, I have a hard time bending it. Under my fingernail, looks a different color than usual (more reddish purple). Anyways this started yesterday, and I was wondering if anyone knew what it could be.