I had this too, so i went to my doctor who sent me to get the 24 hour monitor attached to my chest. It turned out to be ectopic heart beats, i have tablets for it, i don't need to take them really but it stops me feeling the missed beats which is what i didn't like. I was told not to worry about it, but when it's your heart you do worry. The only time i feel it now is when I'm really tired. Don't be afraid, go to the doctors and get it checked. I'm 43 and I've had it for about 10 years. Being overweight
doesn't help either, so if you are then try losing a bit. Hope this is of use to you.