I am a registered nurse that works about two or three days a week. Recently I noticed a knot near or on my acromioclavicular joint and I have numbing pain down my arm and into my hand esp when it s outstretched. It sometimes makes me feel like I will have to put my arm down or drop what is in my hand. I don t remember fracturing it except last winter I did fall skiing and had quite a jolt. I am a bit of a stoic person and I take care of kids, husband parents and patients before I notice I have an issue. It came on after I was watching a friends six month old infant a couple of days a week for her. He weighs about twenty pounds.