Appendicitis: This condition is a common cause of right mid abdominal pain, often accompanied by back pain. The pain typically starts near the navel and then moves to the right lower abdomen. Appendicitis is a medical emergency that requires prompt surgical attention.

Kidney Stones (Nephrolithiasis): Pain from kidney stones can radiate to the back and may cause severe abdominal pain, especially if the stone is moving down the ureter. The pain is often colicky in nature.
Pyelonephritis: An infection of the kidney, pyelonephritis can cause flank pain, abdominal pain, and back pain, along with symptoms like fever and dysuria.
Diverticulitis: Although more common on the left side, diverticulitis can occur on the right and cause abdominal pain that may radiate to the back, especially if there is an abscess or perforation.
Gastroenteritis: Inflammation of the stomach and intestines can cause abdominal pain and may radiate to the back, accompanied by symptoms like diarrhea, vomiting, and fever.

Ectopic Pregnancy: Although more commonly associated with pelvic pain, an ectopic pregnancy can cause abdominal and back pain. It's a life-threatening condition that requires immediate medical attention.
Aortic Aneurysm or Dissection: Abdominal aortic aneurysms can cause back and abdominal pain, especially if they are leaking or dissecting. This is a medical emergency.
Pancreatitis: Inflammation of the pancreas can cause severe abdominal pain that radiates to the back. It can be life-threatening if not promptly treated.
Pulmonary Embolism: While primarily a respiratory issue, a pulmonary embolism can cause referred pain to the abdomen and back, especially if the embolism is large.

Intestinal Obstruction: A blockage in the intestine can cause severe abdominal pain, vomiting, and constipation. The pain can sometimes radiate to the back.
Inflammatory Bowel Disease (IBD): Conditions like Crohn's disease and ulcerative colitis can cause chronic abdominal pain and may radiate to the back, along with symptoms like diarrhea and weight loss.
Abdominal Wall Hematoma: Bleeding into the abdominal wall muscles can cause localized pain and may radiate to the back, often associated with trauma or anticoagulation.
Retroperitoneal Fibrosis: A rare condition characterized by the proliferation of fibrous tissue in the retroperitoneum, which can cause back and abdominal pain due to the encasement of structures like the ureters.