Write an article based on this summary:

Watch for limping. Keep an eye out for other mobility issues. Observe changes in posture. Take note of your dog's breathing. Check your dog's eyes.
One of the most obvious signs of pain is limping. Limping occurs when it hurts to put weight on a leg.  If a leg is causing pain, they are less likely to use it, and sometimes may rely on the other three legs. Dogs in pain will also typically move around less. Aside from limping, you may see other mobility changes. For example, your dog may have trouble getting up or down. It might also move around more slowly than usual, or show a reluctance to do certain activities. Hesitance to go up or down stairs, run, or jump can be a sign of pain. Note the position that your dog holds its head or tail. Any change from normal posture, such as a hanging or tucked tail in a dog that normally has an active tail, can be evidence of pain.  If your dog is holding a leg differently than it normally does, it could be a sign that it is in pain. Pain may also cause your dog to stand with its back arched or to be very stiff when standing or moving. If your dog is in pain, you may see an increase in their respiratory rate or heavy panting. A dog that pants persistently, especially in cool weather, may be in pain. Your dog's eyes can tell you a lot about any pain it might be experiencing. If there is pain in the eye area, you may see squinting, redness, cloudiness, or a discharge.  Your dog also may be rubbing at the area that hurts. If your dog rubs around its eyes frequently, this could be a sign of discomfort in this area. The eyes can also give you a clue about pain in other areas. Squinting can be a sign of pain in the eye area, but some dogs will also squint when they are experiencing pain elsewhere. Dilated pupils can also be a sign that your dog is in pain.