I have the exact same problem. It is most likely harmless.
I can also crack my knee and elbow joints, my neck, my spine (by twisting), knucles, etc.
You might just have loose joints like me.
The difference being I have always had this and it has only gotten more noticable (in my shoulders) since my strength training has over developed some of the major muscles (pecs) which tends to pull my shoulders foward.
I also sit at a desk all day at work which makes it worse.
I went to a doctor and asked his professional opinion of course and he said it was nothing. Then I went to a physio and he said it was also nothing but has given my some exercise to strength the shoulder muscles.
If this is something accute with you (that is it just started happening all of a sudden) - GO AND SEE YOUR DOCTOR!
I combat the rolled foward shoulders by incorpating some horizontal pulling movements (rows) into my training. I have not noticed a difference yet however.
I'm not sure if I would call this "shoulder death". There is a difference between a painful grinding and cracking (like you do your knucles).