Hi 4Mom, When I had my surgery and during my stay at the hospital, I had a cough similar to your mom's. The doctor told me that I was sensitive to the pain killers. I don't have an answer for why it would be persistent after the hospital stay. Mind you, right now, I'm not taking any pain killers except Advil once in a blue moon. Good luck...
Was your mother "tubed" when under the anesthetic? Sometimes the tube causes a persistant throat irritation. A mixture of honey and lemon juice seems to help heal and ease the throat. Mix it with some warm tea. No sugar though.
That's interesting....my mom has the exact thing you describe. She had the surgery, was diagnosed with stage 3c ovarian cancer, and now has a persistant (shallow) cough. She has had it for the past 4 months and nobody can figure out what it is. Sorry I can't offer any suggestions, but I'm curious if you get any answers.