Hi I'm Not Sure Yet What's Wrong But I Have

Hi I'm not sure yet what's wrong but I have a bad cough and I'm congested in my chest and head. Every time I burp I hear my left hear make a swoosh noise like there's fluid behind my ear. I am on a decongestant and I'm getting as much out as possible but sleeping at night is the worst. Even sleeping propped up on pillows. The cool most humidifier made it worse. What could be wrong?