Dear ...... increased bronchovascular marking in ur case is a indication of chronic bronchitis as u hv been a smoker. Smoking triggers inflammatory response in Respiratory tract ...n hence due to continous smoking bronchi gets inflammed n causes congestion in associated blood vessels..which can be seen in x ray as whitish threads spreading away from the centre in both sides...These will cause improper oxgenation and gas exchange in ur lungs..and evolve symptoms like cough fever . If at this stage u dont quit smoking ..then ur lungs will enter the stage of emphysema that means a irreversible disease . Stop ur smoking n consult physian to get proper antibiotics n measures....good luck