As your dog ages, she's more prone to achy bones, joints, and muscles.
Many dogs are worse in cold weather and first thing in the morning.
Arthritis is common in older dogs, and while no cure exists, treatments are available that can make your pet comfortable. Your veterinarian may prescribe buffered aspirin, food supplements, or anti-inflammatory medications, all of which your pet may need to take for the rest of her life. For your part, you need to make sure your pet is not overweight and is consistently, but not strenuously, exercised.