I hope you are doing well, it sounds like you are tolerating a low ejection fraction pretty well, if you are only having SOB with exertion. Do you have problems while laying down flat, without head raised for more than a few minutes? Do you have any pains, or ever come close to passing out, or have visual disturbances?
Approx 1/100 people are born with a bicuspid (instead of tricuspid) aortic valve and it can start affecting a patient at any age, but usually starts causing symptoms at around your age. There is nothing to be done except valve repair/replacement, if it is this.
I would highly recommend being seen at the Mayo Clinic, or a heart valve specialist group which is also very experienced, if you have the option to do either.
Good luck, and keep taking care of yourself as well as you do, but I would take it easy on any possibly vigorous cardio workouts until you know what's going on exactly.
Thanks for the responses! These are greatly appreciated.
When my heart was checked with a stethoscope on 19/18/2017, the murmur was heard in the lower left quadrant. So I assume this would be the aortic valve. As indicated in the posting by @srounkle this could very well be the issue. I also have read that this condition is most prominently found in men. I still do not rule out the fact that my joint swellings began at the same time as the shortness of breath. Maybe I contracted some kind of bacteria which caused the valve to malfunction? If that is the case, I am hoping that maybe if that bacteria has stopped then the valve could heal. Also, over the past year my shortness of breath was getting less and less and then over the past couple of months, my condition deteriorated somewhat. Something which happened about two months ago was a very painful toothache and the dentist said the tooth was draining. I have now had that teeth pulled. In addition, I had a return of a painful joint in my thigh.
Overall this currently does not cause major changes to my lifestyle (other than I am unable to jog 6 miles like I did in the past). However, day to day activities are mostly normal. I normally only have symptoms when exercising and not when laying down; no passing out; no visual disturbances. I am currently on no pharmaceutical drugs