My son was in contact with a friends father that was admitted with pneumonia but we notified now that he tested positive for covid. must my son get tested? he is not sick just have a slight cold

COVID symptoms: COVID symptoms vary widely from person to person. Your sons "slight cold" may be all the symptoms he will exhibit. Since he was in close contact with an infected individual, it would be best to get tested and follow isolation precautions rather be a carrier and put other people at risk. This is the way you break the chain of infection.