hi there, your partner seems to be suffering from obstructive lung disease
. You need to get her pulmonary functions done and visit a pumonalogist to rule out asthama or any other cause of COPD
. If she is a smoker then she has to quit smoking
at the earliest .In the meanwhile she can take some steam inhalations and a mild thumping on her back to dislodge any mucous plug and to expectorate it out should be done, do not use any cough
sedative or over the counter cough syrup without getting a prescription first. The level of breathless ness is not very severe now but do not neglect and get an opinion as soon as possible. Take care.