<<Disclaimer:  Verify this information before applying it to your situation.>>

I also have the same problem.  I felt this gradually coming on and then
a year ago my arm became so bad I could not use it and the pain was
excruciating.  I had several months of physical therapy which helped some
and then stopped.  The pain comes back whenever I do anything other than
the bare minimum--I can't vacuum, clean windows, scrub floors, weed the
flower bed, etc.  I have a hard accepting that as one Dr. put it, "I have
a physical impairment."  Believe me, I have spent hundreds of dollars
trying to find an answer to the problem, but no one has that answer.  Maybe
it is related to sprue . . . but then again can we relate everything to
sprue?  Have a good day.