jay,
I had what you have, I went through the testing (EKG, Xray, etc), plus had a scope put into my heart to look for "disease".The doctors didn't see anything bad.
This is a disease like many others where doctors say the same thing;
1 you have it
2 we don't know why
3 we don't know what will happens
4 if it gets worse, come back, we can put in a pacemaker.
Right side block is better than left side block by the way, so you have the better of the two.
I solved mine by breathing slower, but it took a year. I know, sounds absolutely ridiculous, so here's some more info to hopefully make you think about breathing and how it really kicked my butt. It's called "hyperventillation" if you search on the internet.
Here's a test, breathe 5x in/out....in/out and see how long it takes. Then do the same thing, but after you exhale, wait to inhale until your body tells you to, like holding your breath underwater and you feel the need to breath. What happens is you breathe 12-15x per minute normally and the body only really needs to breathe 3-4x per minute (after you practice breathing very slowly). Ask yourself why you can breathe 3 times slower and have no affect. Our body is terrible at letting you know that you're overbreathing. Ask yourself if overbreathing might be bad for you. I'm 100% certain it caused my right side bundle branch block problem.
Stress and age and sometimes bad habits make people breathe faster and the human body isn't smart enough to give you good feedback to slow down your breathing. Most fast breathers raise their chests when they inhale. You have to actually make your stomach push out on the inhale while your chest lowers. See what you do.
This is something that takes a real leap of faith on your part to research and practice and do consistently. After all, it sounds ridiculous that breathing too fast is really bad for you since you don't feel anything.
I hope you research it. It'll save you alot of pain.
Good luck.
Kevin.