Could my partner have COPD?

Hi. My partner has been through so many tests to find out why she has this persistent cough since her heart attack a year ago. She lacks breath when shopping and has to sit down often and coughs up numerous amounts of phlegm morning, day, night, plus constantly wakes up coughing her lungs up which disturbs both our sleep patterns. CT scan came back normal. Lung tests she couldn't complete because of her coughing. Came out poor. Ruled out Asthma. I'm on the path of chronic bronchitis?? She gets out of breath easily and cant walk far at all. We have to hold onto her to help her with walking when in the shops or anywhere else for that matter. Our friends have helped out when we've been with them so they know how she is. But the lung specialist came out with. There's nothing wrong with you. How rude. Just because the scan came back clear. He was useless. Theres something wrong somewhere. Any ideas or other avenues we can pursue. Cheers.