Chest Pain

I have been have left side chest pains. Many test were done. So far no conclusions.
I now use nitro spray to alleviate pains that I once accepted prior several months ago.
The only common denomenator appears to be stress related. But I am concerned that daily regimen of zero to six times a day could be a problem. Many tests were done. My family doctor wants me to loose weight. Sofar in the past year I lost fourty pounds. That has not alleviated the pains to any degree.
I have had chf in 1995. Recovered and did a lot of since then. Now I get exhausted after an hour at gardening...
Can you give me additional ideas, my family doctor, my cardiac physician, and freinds do not have a solution...

thanks,
Richard