I have dry cough with crackling chest.it was start like normal cough 3weeks before.i have no fever but only dry cough.is it symton of viral disease?

Get a chest XRay: Dry cough or any cough for 3 weeks needs to be seen by a doctor , get a cr scan of chest may be, since chest x ray can miss certain lesions. In the future any cough more than a week needs to be seen by a doctor, meanwhile stop smoking

Possibilities: Crackling sounds can be from fluid from pneumonia but could also be a sign of lung disease caused by scleroderma. First find out whether the crackling is wet or dry. If dry a rheumatologist will likely have the answer.