Talk to Pulmonologist / Lung on Frequently Coughing

From about past 2 years, i had been victim of coughing quite frequently. After every 2 to 3 weeks on average, I somehow catch cough which then lasts for about 5 to 6 days normally. (often get quite out of control gradually). Could someone please guide me about some tests which I should go for to check where the problem is? and whether everything is okay inside?