basnet,
Hello and welcome to HealingWell. I am so sorry your son is having this problem. It does sound like he has trapped gas in his stomach and that may cause the shortness of breath as well as the anxiety he is experiencing. Running in his room is certainly going to aggravate his problem.
I am not a professional but perhaps it is time to make an appointment with a GI Physician and have him evaluated. This may be a problem that medication can help and he will feel much better.
Please keep posting as we are here to support you.
Again a warm welcome to you.
Kitt