Pain under the upper left rib cage can be a symptom of problems with the spleen, according to WebMD. Another cause of pain under the left rib cage may be diverticulitis, says Mayo Clinic.
A viral infection can cause an enlarged spleen, as can some blood cancers or a cancer that has spread from another site to the spleen, according to WebMD. The spleen can become enlarged because of a liver disease, injury or infection by parasites or bacteria.
The pain caused by an enlarged spleen begins on the upper left side of the abdomen and radiates to the left shoulder, according to WebMD. The pain is worse when the patient tries to take a deep breath. He has difficulty eating large meals and may be fatigued or have unexplained weight loss. As the spleen is part of the immune system, his body has trouble fighting infections. He also bleeds easily and develops anemia and jaundice, which is a yellowing of the eyes and skin and darkening of the urine.
Diverticulitis is an inflammation of pockets that form in the large intestine, says Mayo Clinic. The pain, which is felt on the lower left side of the abdomen, is severe and can last for days. Other symptoms are nausea and vomiting, fever and a tender abdomen.