My check-up resulted in the prognosis.... Multiple prior studies,most recent 10/11/2013....Findings...A Linear density is seen in the the right mid-lung which was not previously apparent.The lungs are withoutout other abnormal density The heart and pulmonary vascularity are normal.
Thanks for your question on Chat Doctor. In my opinion you should first consult pulmonologist and get done CT THORAX to rule out plate atelectasis. This is segmental partial collapse of lung mostly due to retained secretions in the lumen. So small segments can cause partial collapse and produce linear(plate) atelectasis.  And this can be seen as linear density on chest x-ray. So CT THORAX is must rule out this. Treatment for this is chest physiotherapy and antibiotics.  With proper treatment, it is reversible condition.