You should see your GP. Do you have a cause for this pain - that is chronic fatigue form a monotonous role for the left side? Been in any accidents? Does your family have a history of cardiac disease? Do you smoke? Abuse drugs? Do you have any history of numbness in your arms or legs? IF your GP is astute, s/he will ask you all of the above and more.

Depends where spiral or gastrointestinal.

Pain on the left side can be caused from anything from a pull or strain to pain from organs that are part of your body including the pancreas, the stomach, small intestines, the kidneys, ovaries and Fallopian tube. To really evaluate the cause of pain you should be seen by a health care professional and have some test run.