The most common reason a lump appears in the stomach is due to a hernia, which is a weak spot in the abdominal wall, according to MedlinePlus. The lump is due to the internal organs pushing through the muscles in the abdomen.
A hernia may appear after lifting a heavy object, straining or excessive coughing, explains MedlinePlus. There are several types of hernias, but only a couple of types appear in the abdomen. An incisional hernia may appear through a scar following surgery in the abdomen, and an umbilical hernia presents as a bulge near the belly button. The most serious type of hernia is the strangulated hernia, which means there is no longer a blood supply to the organ. Though this is a rare condition, it is an emergency.
People who have a hernia that is bothersome must contact a doctor in case the condition becomes serious, claims MedlinePlus. An individual should contact a doctor if the hernia is painful or changes appearance or if he experiences a bloated feeling. Fever, nausea and vomiting are also signs that a doctor's expertise is necessary. The doctor examines the hernia, asks the patient specific questions about the hernia, and may suggest surgery in cases where the condition has the potential to become dangerous or troubling to the patient.