My mom is 48 yrs old in 2020 suddenly one night pain started in her right chest pain was much we went to doctor he done CT and report comes with pleural effusion of right chest, doctor give her medication the chest water has shrink after 5,6 months she now she is continuously taking other medicines, but she not completely good that was before effusion, Doctor said she has some scars of effusion and it will stay always, doctor always done spirometer breathing test and makes a report"early small airway disease" and doctor said she has some blockages in air pathway . I want to know what this small airway disease, is asthma or COPD , please help us to describe the disease.