How do I get rid of this chest congestion and this cough?

Cough syrup. You may have a simple bronchitis. However, you did not say how long you have been coughing. Your physician should be able to get a more focused history and make sure you do not have a pneumonia. A cough syrup, a bronchodilator, or an antibiotic can help alone or in combination.
How long have you. How long have you had the chest congestion and cough for? Do you have any lung issues or do you smoke? Any other medical problems? These factors will affect how your cough and chest condition are treated. Check in with your doctor.