Hi I Have An Indentation In My Posterior Shoulder When

Hi I have an indentation in my posterior shoulder when



when your arm goes around and it looks like a scar in the hole ...almost looks like a hole in my arm the only thing I can think of is I just lost 80 pounds and I have very bony shoulders could that be it? It's like a dimple in the shoulder...I did not do any damage and there is no pain whatsoever. And it's only on one shoulder