At 8 years old your lab is getting to a geriatric phase of life and although you may feel he is "doing fine" I do not think he is. Every animal as they age develop changes in behavior, much as people do.
Your dog has degeneration in his joints, slower from laying to standing, decrease jumping up on high places, and reluctancy to slick surfaces. They know that as their limbs slide around it is harder to control them and more discomfort. Dogs have very limited ways of showing things, esp Labs who will be happy for you no matter what.
Tight spaces can be an aging phobia related to just plain fear, a decrease in visual ability & fear, or fear of being bumped into and experiencing pain.
There are wonderful anitinflammatory drugs to help these aging dogs. I ask that you give me the benefit of the doubt, call your vet and ask for a 2 week trial of Rimadyl or Metacam and see how your dog does.
Dr.V
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Dr. D.A. Vamvakias
Veterinarian
