My dog’s belly is hard and swollen, twitching, and crying in pain

A very hard, swollen belly with crying has many causes; take the dog to a clinic promptly for X-ray and abdominal ultrasound to find the reason and treat it.

First, intense crying usually means acute abdomen such as gastric torsion, intussusception, or acute gastric dilation, needing emergency surgery. Second, food bloat or constipation needs digestion and laxative aids. Third, gas or blockage from bad diet or foreign objects needs vet care if probiotics and less food do not help. Fourth, ascites or tumors from various causes enlarge and pain the belly. This is serious; do not self-treat, get professional help.