Pearl, you mention that this mom has pain in the breast that is not
being nursed from, and that it alternates(I think that's the word you
used) when she nurses on other side? it sounds like it could be painful
letdown- I experienced, at various times during my nursing career (not
over yet!)
letdowns painful enough to make me grimace and clench my teeth.
 I wouldn't call it "excruciating", as you describe it , however.
But what is more bearable to one is excruciating to someone else...

Ellen Vegh, LLLL in Pittsburgh, PA