A short time ago, several were stating posts about lumps on the arm. Have a look at the Mail on Sunday 17 April issue [UK] and see in the health section if it is of any help. There is a diagram and blurb at the bottom of a page. I have cut it out and will be taking it to the GP when I have time and asking if it is????? This point may help others or may not. What you do with this info is up to you and I am not diagnosing in any way. Just it sounded like the troubles I have on my arm as a result of an accident.