Old dog, new symptom, vet time. I have no idea, a lot of things can cause louder breathing.
Amanda & Bevo 2015
Libby's Monkey N The Middle, CGC, RAE, BN, CD (Bean, Chinese Crested, 1/26/08)
Fluffy, Cairn Terrier, gotcha 6/10
Gaea's Pandemonium By Request (Chaos, Chinese Crested, 2/14/12)
Mischief N Miracles, RAE, CGC, #1 Parson Russell Terrier in AKC Rally, 2009 (Emma, 10/13/03-1/8/10)
Jewel, Italian Greyhound, 9/15/01-7/7/12