After reading the excellent Dr. Petty’s Pain Relief for Dogs, by Dr. Mike Petty, a “pain vet” working with cutting-edge research to help relieve canine pain, there were standout parts we just had to share with you, namely: age should never be used as an excuse for an animal in pain; our pets feel as much or more pain than we do; and there is a treatment out there for every dog.
As your dog’s foremost companion, you have an advantage over even her vet in assessing whether your dog is in chronic pain. Talk to your vet if you see any of these 15 symptoms of pain.
#1 Reluctance to walk on slippery surfaces.
#2 Going up or down stairs.
#3 ecoming selective about what to jump up onto or down from.
#4 Attempting to stand up with the front legs first.
#5 The simple task of lying down may actually become difficult.
#6 Running and jumping activities become more limited.
#7 Placing an abnormal amount of weight on his front legs.
#8 Abnormal wear on nails.
#9 Unwillingness to initiate play or other social interactions.
#10 Aggression toward other animals where no aggression existed before.
#11   Aversion to being petted or brushed.
#12 Disruption in sleep patterns.
#13 Stiffness.
#14 A decrease in appetite.
#15 House-training issues.

– See more at: http://moderndogmagazine.com/articles/15-signs-your-dog-pain/91754#sthash.i7JUGy2k.dpuf