Hello I Have A 3 Year Old Son Who Has

Hello I have a 3 year old son who has been coughing for several days now. He has not shown a tempature or any other symptoms. The cough is producing mucus and hard for him to sleep at night, I can't get him to spit it out he just keeps swallowing it. Should l take him in and have him evaluated? Or use over the counter medication till it goes away?