I think that patients who complain about sleep apnea or similar breathing difficulty should take pulmonary function tests.
Special devices and mouthpieces are used to test the effectiveness of air flow in and out of the lungs and rule out the possibility of lung disease.
I had sleep apnea for a long time before knowing what it was. Finally my doctor had me take these tests and they revealed the condition; at least it wasn’t lung disease.
I only wish that I had known about the tests earlier, so I would have quit fretting that I had something like a heart condition.