Why is my stomach swelling?

Abdominal swelling: When you say "swelling" are you relating your abdominal circumference to feelings of distension, fluid retention, constipation, overeating, or do you feel pregnant? Hard to answer your question without further information and clarity. Over what period of time have you noted the swelling--minutes or months, and what are your underlying medical problems (alcohol, liver disease, gut problems...)?

What?: Are you female? Are you bloated and gassy? Are you constipated. I need a bit more info to answer this question.

Abdominal distension: Regretfully not enough information the differential diagnosis includes far to many conditions both benign and serious.