<Mom has been complaining re a deep radiating pain in lt. breast, that starts
     at the base of the breast (7 o'clock position) and radiates to the
     nipple - ..... following a feeding the mother states that the deep radiating
     pain can last for as long as two hours and is accompanied with deep
     feeling of being itchy in the breast - does this sound like deep duct
     candiasis?>
Yes, sounds like thrush to me. I would suggest more antifungal treatment- either oral
nystatin, 2 caps 3 X/day, or oral fluconzole if she can afford it. Also, treating baby
and cutting out sugar and alcohol from mother's diet. The pain is often not so bad after
expressing, so if she needs a break from pain she could try expressing on the bad
side for a few feeds. Reassure her that most women with thrush do recover, but there is
usually not a quick fix treatment.
When thrush pain is persisting and people wonder why, I remind them of other fungal
infections, like tinea on the feet which you must treat for weeks (Just quietly, I have
been treating my 10 yr old daughter's foot for months. Don't tell her I've just told the
whole world! :) ).
Lisa Amir
GP / IBCLC  in Melbourne, Australia