I don t know if this helps, but I had all of the same symptoms and was under the assumption that I had a heart murmur. Turns out that the murmur was misdiagnosed and I have a congenital heart defect called Atrial Septal Defect. (where the hole in your heart is between the top two chambers instead of the bottom chambers like a murmur) It is repairable by surgery if it is bad enough, but most of the time it is just left alone. I would talk to your doctor about it, have him/her refer you to a cardiologist to do some tests. I had to have a TEE(a ultrasound from inside the throat) to find my defect. Good luck ...my heart problem scared the crap out of me until I found out more about it. God Bless and take care of yourself.