Thank you for your query. Would you clarify a few things for me? 1) has she had any surgeries in the abdomen or chect? 2) has she had any trauma to the abdomen or chest (a fall, or pressure during sudden breaking while driving)? 3) how long does the episode last for? you mentioned that it gets worse if she tries to sit. what else makes it worse? 4) does lying down trigger it? and when she sits up, does it get relieved after a while? What makes it better? does the breathlessness lead to any bluish discolouration of lips, earlobes, face, toungue, extremities? 5) is she overweight? 6) any family history of heart defects, disease? any sweating or palpitation associated during the episode? 7) does she have any other medical problems? is she on any medications? Given her age and symptoms, the possibility of a diaphragmatic hernia is present (acquired). This can be diagnosed by an ultrasound/CT with a strong clinical suspicion. I would also like to rule out heart based pathology such as compromised blood flow ( temporary or chronic), structural defects. Any chest pain ( at any age) with or without associated symptoms need to be checked out by a medical professional immediately. I recommend taking her to a physician right away (equip yourself with the answers to the above questions, may come in handy). If she develops severe abdominal or chest pain (including neck and arm pain), loss of consciousness, breathing difficulty, sweating, ligtheadedness/giddiness, take her to the ER right away. Hope this helps. Please feel free to contact us should you need further clarification. wish you both good health