Or should I take mucolytic or antitussive?

Depends on cough. Mucolytics are used to thin secretions and mucus - we use it in copd, sinusitis, and other things. The goal of which is to help get mucus out of the lungs through a cough. Antitussives are on the other end of the spectrum - they work to block or suppress the cough. Whether you use a mucolytic or antitussive really depends on the cause of the cough in the first place.