Hiya Aphro,
I am not a medical doctor but write this because I have had it myself
Just one thing I noted in your post. You say when you bend forward the pain goes. Ask your doctor to investigate pericarditis. This is not a heart problem, but inflammation and sometimes infection of the pericardium which is the sac that surrounds the heart muscle. Relief from pain (in most cases) is brought on when you bend forward because the fluid in the sac (the pericardium) moves and takes the pressure off.
It cannot be diagnosed by ecg as the heart is a muscle and the pericardium is a sac around the heart. It is diagnosed by doctors hearing a "scratching" in the area when they use a stethoscope. Don't worry, it cannot lead to heart attacks, so don't be afraid.
It is worth asking your doctor about it. As I stated previously, I am not medically trained but can only offer this up as I have had pericarditis myself of an on for a number of years.
Hope you can get it sorted out. Let me know.
goldenwings