My son, who is 15 years old complained of difficulty breathing, as if there's tightening in his throat. Likewise, it feels like he can hear his heartbeat. I tried asking him to take deep breaths but it didn't seem to work. I asked him to drink lots of cold water but the tightness feeling comes back once he stops drinking cold water. Could this be due to the heat? The temperature in are room is extremely warm. Or could his intake of coffee, which he is not used to produce such effect?