I agree w. Jerry totally...you need to see a heart doctor not your primary care doc. Heart docs only deal with the heart and know just about everything that there is to know about it. As far as your family history goes...what most docs look out for is if anyone in your family has had a heart attack under the age of 50 as well as there being a history of blood clots primarily in their legs. Swelling in the feet and legs usually isn't a great thing and should definately be checked out because many times it does come up to be heart related.....if for no other reason but to set your mind at ease i would just ask your family doc for a referral to a heart doc just to do a general check up...it can't hurt and may just set your mind at ease...good luck to you....
Based on personal experience, I do think murmurs can come and go depending on what is going on with you. For instance I had a heart murmur when I was younger that could be heard when a valsalva was performed. Doctors sometimes heard the murmur when I was sick with the flu. I have been a long distance runner, and was also told on one occasion that runners can develop a murmur simply due to the power of their hearts. In the words of one doctor: "they get an extra swish as the blood blows past the valve".
Your family or primary care doctor is a good place to start. They should be able to tell you it is best to see a specialist and which one to see. From what I read I think you need to be examined by a Cardiologist.. a heart doctor.
Stress and anxiety can cause heat symptoms, and if the symptoms stop when the stress is removed, I'd say it isn't a heart problem.