Musculoskeletal strain or injury: This is often the most common cause of sharp pain on one side of the torso, resulting from overuse, trauma, or poor posture, leading to muscle or ligament strain.

Costochondritis: Inflammation of the cartilage that connects the ribs to the breastbone, which can cause sharp pains on the side of the torso.
Precordial catch syndrome: A condition characterized by sharp, stabbing pains in the chest or side, often related to the muscles between the ribs.
Gallbladder disease: Gallstones or inflammation of the gallbladder can cause sharp pains in the right upper quadrant but can sometimes be referred to the left side.
Kidney stones or pyelonephritis: While kidney issues typically cause flank pain, severe cases can radiate to the side of the torso.

Pulmonary embolism: A blood clot in the lungs, which can cause sudden, severe chest pain that might be felt on one side of the torso. This condition is life-threatening and requires immediate medical attention.
Aortic dissection: A tear in the aorta's inner layer, which can cause severe, tearing pain that often starts in the chest and radiates to the back or side.
Pneumothorax: Air in the space between the lungs and chest cavity, which can cause sudden, severe chest pain that might be localized to one side.

Sickle cell crisis: Individuals with sickle cell disease can experience episodes of severe pain due to vaso-occlusive crises, which can affect various parts of the body, including the torso.
Herpes zoster (shingles): Reactivation of the varicella-zoster virus can cause a painful rash that might initially present as sharp pain on one side of the torso before the rash appears.
Tumor: Rarely, a tumor in the chest or abdominal cavity can cause localized pain, depending on its location and size.