I have a knot on my shoulder the size of a strawberry. It is really bothering me. I've had it for over 5 years.
A shoulder mass that has not changed in size for five years and not causing any symptoms such as weakness, numbness, tingling, or decreased range of motion it is probably not a cause for concern.
It could be a benign fatty tumor a cyst or something else. Since it is bother you it is worth having it evaluated by your physician.