This dog needs to be examined by a veterinarian immediately. Painful, hard, and distended abdomen could be a sign of bloat aka GDV (gastro-intestinal volvulus). This can be a life threatening problem. There are other serious causes of intense abdominal pain--foreign body obstruction, pancreatitis, or trauma could explain these signs. Have this dog examined so your veterinarian can identify the cause and start appropriate treatment.
You should inform about other symptoms that your dog is showing. Note for following symptoms in your dog.
- Unproductive vomiting
She may be either constipated or swallowed something. You should call your local vet.
She might have worms and you can give her dewormer meds from a pet store or a walmart!