Left-sided chest pain

What would be the possible causes of a dull-like ache on the left side under breast?  This "pain" is evident when I awake.  As the day progresses, it subsides somewhat and by evening it is usually gone only to re-appear the next morning.
(I have recently had a stress treadmill and no problems were found.)
Thank you,
Mary

[Cleveland Clinic, MD]

Dear  Mary,

There are many causes of chest pain.  The one that doctors worry about the most is cardiac because it has the potential to be life-threatening.  Once this is ruled out the work-up can proceed at a more leisurely pace.

Amongst the cardiac causes of chest pain are: ischemia (due to blockages - including both stable and unstable angina and acute heart attack and coronary artery spasm), pericarditis (inflammation of the sack around the heart), myocarditis (inflammation of the heart), cardiomyopathy (heart failure) and rarer causes such as coronary artery dissection, acute rupture of the heart and valves and infections of the pericardium.

Gastrointestinal causes of chest pain include reflux (acid from the stomach washing back into the esophagus), gallstones, esophageal spasm, esophageal rupture, varicose veins of the esophagus, strictures of the esophagus, tumors of the esophagus and other less common GI problems.

Pulmonary (lung) causes include pneumonia, pulmonary embolus, pneumothorax, pleuritis and bleb rupture.

Other potential causes are aortic dissection, back and spine problems and musculoskeletal (muscle strain, rib fracture, etc.).

Psychological causes of chest pain are common and include panic attacks, anxiety, stress and mental duress.

As you can see the list of potential causes in long and may take a little bit of time to determine the precise cause.  A good Internal Medicine doctor should be able to work through the potential causes of your symptoms.