For me the ache was on my back as well as the arm along with a headache and a mild temperature increase. I took some Acetaminophen and was just a bit less active than usual.
Alex
"There is a cult of ignorance in the United States, and there has always been. The strain of anti-intellectualism has been a constant thread winding its way through our political and cultural life, nurtured by the false notion that democracy means that "my ignorance is just as good as your knowledge."
-- Isaac Asimov