Occasional pain on the left side of the chest must be considered as a heart problem, commonly caused by angina pectoris or coronary heart disease. Go to the hospital for a heart-related examination, commonly an electrocardiogram (ECG), preferably at the time of the onset of pain. However, if you don’t know the time of the onset of pain, you can do a 24-hour or even 48-hour ambulatory electrocardiogram to capture the electrical changes in the heart during the onset of pain, and you must also improve the ultrasound of the heart or the exercise plate. To confirm the diagnosis of coronary artery disease, a CTA of the heart, also known as a coronary angiogram, can basically confirm the diagnosis. If the heart is excluded and the left side of the chest still has recurrent pain, intercostal neuralgia is considered to be the main cause, and this situation can be treated symptomatically.