Pneumonia: This condition often presents with shortness of breath, fever, and can cause abdominal pain if the pneumonia is severe enough to cause referred pain or if there's an associated condition like a pulmonary embolism. The combination of respiratory and systemic symptoms makes pneumonia a leading consideration.

Gastroenteritis: Inflammation of the stomach and intestines can cause abdominal pain and fever. If severe, it can lead to dehydration, which might cause shortness of breath.
Pancreatitis: Inflammation of the pancreas can cause severe abdominal pain and fever. Shortness of breath can occur if the condition leads to complications like acute respiratory distress syndrome (ARDS).
Cholecystitis: Inflammation of the gallbladder can cause right upper quadrant abdominal pain and fever. Shortness of breath might not be a direct symptom but could occur if the condition leads to a systemic inflammatory response.

Pulmonary Embolism: A blockage in one of the arteries in the lungs can cause sudden shortness of breath and chest pain, which might be referred to the abdomen. Fever might not be present but could occur if there's associated pulmonary infarction or infection.
Sepsis: A life-threatening condition that arises when the body's response to infection causes injury to its own tissues and organs. Sepsis can present with a wide range of symptoms including fever, abdominal pain, and shortness of breath, especially if the infection is in the abdomen or lungs.
Cardiac Conditions (e.g., Myocardial Infarction): While primarily associated with chest pain, myocardial infarction can cause shortness of breath and, in some cases, abdominal pain if the inferior wall of the heart is involved.

Eosinophilic Pneumonia: A rare condition characterized by an accumulation of eosinophils in the lungs, which can cause shortness of breath and fever. Abdominal pain might be present if there's an associated eosinophilic gastroenteritis.
Tropical Diseases (e.g., Malaria): In areas where these diseases are prevalent, they can cause a wide range of symptoms including fever, abdominal pain, and shortness of breath, especially if there's significant anemia or organ involvement.
Lymphoma: Certain types of lymphoma can cause systemic symptoms including fever, abdominal pain due to lymphadenopathy or organ involvement, and shortness of breath if there's mediastinal involvement or pulmonary metastases.