Should I Be Concerned About My Recent CT Scan That Shows Mild Pleural Effusion That I Had Three Years Ago?

Hi, a Cat Scan showed I had Pleural Effusion in my lungs. A echocardiogram was done and they said my heart is fine. I was told the the Pleural Effusion was mild and not to worry about it, but three years ago a Cat Scan showed I had Pleural Effusion back then also. So this is the second time that I know of that I had it. Should I just ignore and not worry about it? I cough at night, dry cough, but the doctor told me that it is just acid reflex even though I have no indigestion or burning or any acid feelings at the time I am coughing. I don t notice any symptoms in the day.