I have a painful lump on my right collar bone right at the end by the sternum and it radiates pain to my arm, shoulder, neck. I have had this lump for about 4 years now and it is sometimes painful other times not painful but still present. It is very obvious and can even be seen through my sweaters. I have had night sweats badly for about 2 years now but was pregnant so just figured it was that. I have experienced a great deal of unexplained weight loss for over a year now to the point I dropped to 105 lbs (normally around 120). I figure the lump is probably just muscle nots since I feel it in my neck and shoulder blades but should I be getting it checked it is getting to the point I can barely move my arm.