Unfortunately, dogs can't tell us when they're in pain. They would if they could--because they hurt just like we do--therefore, it's up to us humans to figure it out. Here are some signs to help determine if your dog is feeling pain.
Instructions
A lack of appetite is usually the clearest indication that a dog is in pain or has some type of medical problem. If your dog is not eating or seems to have trouble eating, make a vet appointment ASAP.
If your dog is quiet and unresponsive or just not his usual energetic self, this could be a good sign that your dog is in pain. A couple of days of this behavior also warrants a visit to the vet.
A dog that avoids being petted, handled or lifted could very well be in pain. Sometimes a dog will squeal or cry if you touch the painful spot or may growl if you try lifting her at the spot. In any case, the avoidance of any contact could mean pain.
If you notice your dog is having trouble getting comfortable, this could be an indication he is experiencing pain and looking for the least painful position to lie down in.