Hi I was getting these for a while, then while I was in A&E for another reason they found I had a heart murmur. For the next few months I had quite a few tests and scans done on my heart an they found I had a leaking heart valve. At first I was told I would need surgery at somepoint in my life to sort this but it wasn't require immediately. I then got sent for a camera down my throat so they could get a better view of it just to be sure and they found that the leak was now severe and not moderate, so therefor I required surgery ASAP. So in june this year I had open heart surgery to repair my valve. Since then my hearts beat is normal and no more breathlessness and tiredness, so I would definitely advise you to go to the doctor. it did mess up my life a bit at the time, had to stop uni and was off work a good few months but now I am definitely feel so much better.