Appendicitis: This is often the first consideration for right lower quadrant pain, especially if it's severe, persistent, and accompanied by other symptoms like nausea, vomiting, and fever. The pain typically starts near the navel and then moves to the right lower abdomen.

Gallbladder Disease (Cholecystitis or Cholelithiasis): Pain in the right upper quadrant, especially after eating fatty foods, suggests gallbladder issues. Symptoms can include sharp pain, jaundice, and fever.
Kidney Stones (Nephrolithiasis): Severe, crampy pain that moves from the back down to the groin area can indicate a kidney stone. It's often accompanied by nausea, vomiting, and blood in the urine.
Musculoskeletal Issues: Strains or overuse injuries can cause pain on one side of the body. This could be due to physical activity, poor posture, or other mechanical issues.
Hernias: An inguinal hernia on the right side can cause pain and a bulge in the groin area, especially when coughing, lifting, or bending over.

Ectopic Pregnancy: Although less common, an ectopic pregnancy can present with severe, one-sided lower abdominal pain and is a medical emergency. It's crucial to consider this in women of childbearing age.
Ovarian Torsion: Sudden, severe pain on one side of the lower abdomen can be a sign of ovarian torsion, which requires immediate medical attention.
Pulmonary Embolism: While more commonly associated with respiratory symptoms, a pulmonary embolism can cause sharp, stabbing chest pain that might be referred to the right side if the embolism is located in a specific part of the lung.
Aortic Dissection: This is a rare but life-threatening condition where the inner layer of the aorta tears. It can cause severe, tearing pain that might start in the chest and radiate to the back or abdomen.

Right Lower Lobe Pneumonia: In some cases, pneumonia can cause pain on one side of the chest or abdomen, especially if the diaphragm is involved.
Intestinal Obstruction: This can cause severe abdominal pain, nausea, vomiting, and constipation. The pain can be generalized but might be more pronounced on one side depending on the location of the obstruction.
Pancreatitis: While pancreatitis typically causes mid-abdominal pain, it can sometimes be felt more on one side, especially if the tail of the pancreas is involved.
Diverticulitis: Inflammation of a diverticulum in the intestine can cause pain, usually on the left side, but it can occur on the right side if the diverticula are located there.