This is something i've noticed for years so it might be silly to wonder about it now, but whenever i laugh really hard, i get a phlegmy cough. ?

Stepwise workup: Are you short of breath? Is your cough worse at night? Do you wake up coughing? Are you underweight? Do you have night sweats or excessive sweating? A chest Xray is cheap and should be the first step. An Office Spirometry similarly is an easy test to R/O Asthma or Chronic Bronchitis caused by smoking. Nocturnal Gatric Reflux is also a common and easily ruled out condition.