A hernia is a bulge caused by tissue pushing through the wall of muscle that's holding it in. Most hernias are abdominal hernias. This means they happen in the belly and groin areas.
You may have a hernia if you can feel a soft lump in your belly or groin or in a scar where you had surgery in the past. The lump may go away when you press on it or lie down. It may be painful, especially when you cough, bend over, or lift something heavy.