K.K.
My son does that also and he has asthma. He wheezes during play and it doesn't seem to bother him. I have to get him to sit for a bit because it bothers me. It just sounds like he is in disstress.
Plus the change in climit can bring it on. Is he retracting? Its the retracting that you have to worry more about. That means he is working way to hard to get air in. I take my son to a pulmary doctor and they where able to get it undercontrol.
I would really watch it and get him in soon. Good luck