Abdominal pain refers to the pain felt anywhere in the area between the chest and groin and can involve any of several different organs located in the abdomen. Abdominal pain can range from a mild stomach pain to severe abdominal pain with life threatening complications.One of the most common causes of abdominal pain is indigestion. Indigestion refers to the abdominal pain or discomfort felt during or after eating. It can range from feeling full to actual abdominal pain. Indigestion can be a sign of a health problem such as the gastro-esophageal reflux disease or cancer.It should be noted that some drugs that irritate the stomach, stress, fatigue, and anxiety can also lead to indigestion. Symptoms of indigestion include abdominal pain, bloating, belching, gas, nausea, vomiting, acidic taste, and burning in the stomach or upper abdomen. This should not be confused with heartburn, which is felt in the chest and throat.Another common cause of abdominal pain is constipation. Constipation is the inability to have a normal bowel movement. This can be in the form of having to strain to have pass stools or not being able to have a bowel movement at all.Constipation can be brought on due to simple things such as a change in diet or routine. It can also be caused by underlying health problems. Symptoms of constipation include abdominal pain, abdominal pressure, swollen abdomen, difficult bowel movements, lack of bowel movements and vomiting.Gastro-enteritis, sometimes termed as stomach flu, is another common cause of abdominal discomfort. The pain associated with gastroenteritis is due to the irritation and inflammation of the lining of the stomach and intestines, which can be caused by a virus or bacterial infection. Symptoms of gastroenteritis include abdominal pain, abdominal cramps, nausea, vomiting, diarrhea, swollen lymph glands, fatigue, and fever.Food poisoning may cause mild abdominal pain or a severe life-threatening infection, depending on the type of bacteria or parasite involved. There are many food and water borne illnesses that can cause food poisoning symptoms. The most common micro-organisms to cause food poisoning include Salmonella, E. Coli, and botulism.Symptoms of food poisoning include abdominal pain, abdominal cramps, nausea, vomiting, diarrhea, fatigue, weakness and fever. The severity of the symptoms will vary, depending on the bacteria or parasite involved with the infection.Another related cause of abdominal pain is food allergy. Food allergy is an immune system response to a certain compound in food.  Food intolerance is also another common cause of abdominal pain. It is a digestive response to foods and often due to the digestive system being low in a needed enzyme or sensitivity to a chemical additive. Both food allergy and food intolerance can lead to abdominal pain.Symptoms of a food allergy occur every time the food is consumed and include abdominal pain, nausea, diarrhea, rash, hives, and shortness of breath, chest pain, and anaphylaxis. Symptoms of food intolerance increase depending on how much of the offending food is consumed and include abdominal pain, nausea, gas, abdominal cramps, bloating, vomiting, heartburn, diarrhea, headache and irritability.It is important to understand that every human being produces and passes gas. Gas is naturally formed as the digestive system breaks down food. However, some foods are known to produce more gas than others as the body works on them. These include high fiber foods such as beans, vegetables, fruits, and whole grain products. Other foods that can increase gas in the body include dairy products, soft drinks and fruit juices. An excess of gas in the system can lead to bloating and abdominal pain.Frequent painful gas, commonly known as belching or flatulence, can be a sign of health problems such as ulcers, gastro esophageal reflux disease, irritable bowel syndrome, and colon cancer.