MAC seems to be related to body type. It is possible the pain in your thoracic spine is a myofascial type of pain. See if you can go to a pain management specialist and get trigger shots. If they relieve that pain there is your answer. Depending on your lifestyle and doing the same activity over and over plus the added stress of lung disease , you can develop that- which probably doesn’t have to do with MAC but is painful I am sure especially if it lasts and gets worse before it gets better. Good luck! I’m sorry you have that pain. Irene5