Thank you for all your prayers!
The tests show there are no serious problem with Christopher's heart. The sound the doctor is hearing is caused by something that will go away and not cause him any damage. Also, the chest pains appear to be muscular and the severe shortness of breath caused by his mold allergies growing worse because of the weather. I guess everything came together like a "perfect storm" to cause him to nearly pass out at work a couple of weeks ago.
His doctor had told him if his heart had no problems then they would start running extensive allergy tests to see if he's allergic to something other than mold (which is bad enough).
He was so excited that he called me from an elevator at the hospital. My husband called me a few minutes later to tell me I was the first person Christopher had called and his best friend was the second...to tell him he could (finally) attend their tennis lessons again this evening! They are still on their way home but I wanted to quickly share the good news.
I couldn't go with them as I'm still recovering from the flu, although I'm much better.
I know it was prayer that enabled me to stay calm, as well as the good outcome!