If you have not noticed with other illnesses you have had, a cough is a frequent player in many conditions. However, coughing is a very common symptom with strep throat, since the bacterium tends to infiltrate the throat area. The throat is lined with membranes and when they are infected with bacteria, phlegm is produced and a cough develops as a result. A cough is an adaptation to help the body fight off the infection and physically remove the harmful germs from your body so you can heal. If you have a frequent, deep cough that does not improve, consider seeing your doctor so that you can get proper treatment.