Hi, most common cause of cold is the viral infection, which is usually self limiting with symptomatic treatment.
If associated with secondary bacterial infection, then antibiotics should be started. Blow your nose. Regularly and gently blow your nose if mucus or irritants are present. Humidify. Set up a humidifier in your work or sleep location. Or breathe in the steam from a warm shower to help loosen the mucus in your nose and clear your head of stuffiness. Stay hydrated. Drink plenty of liquids, such as water, juice or noncaffeinated tea. Avoid caffeinated beverages, which can cause dehydration and aggravate your symptoms.