Symptoms of an asthma attack are the following:
Severe wheezing when breathing both in and out
Coughing that won't stop
Very rapid breathing
Chest pain or pressure
Tightened neck and chest muscles, called retractions
Feelings of anxiety or panic
Pale, sweaty face
Blue lips or fingernails
Or worsening symptoms despite use of your medications.
There are also cases of mild asthma attacks which are generally more common. As for your kid, yes you should really talk to his doctor or an asthma specialist. And also remember that the most important thing to control asthma is to stay away from "asthma triggers".
Visit this link for asthma triggers: http://www.cdc.gov/asthma/triggers.html