Hi, bnm127. Welcome to the board.
If you've noticed a difference just in the past few days, no this isn't normal. Best to get him in to see a vet--it could be related to his heart or something to do with his respiratory system, and it's probably not something that you should wait on.
That sounds scary, but if you catch it early, there are treatments out there that can help. For instance, at the age of 11, our setter, Ridge, was diagnosed with congestive heart failure. She was put on enalapril, VetMedin, and furosemide and is now 13 and still going strong. So it's best not to wait--these things can spiral out of control quickly if not treated.
I hope the vet can give you good news!
