Thank you for the additional information.
There are many possible causes of left sided chest pain. When the pain is felt in one or more of the ribs, the most common cause would be from musculoskeletal inflammation. The most common is inflammation of the joints at the ends of the ribs, called costochondritis.
The most worrisome cause of chest pain is from heart disease, but heart disease will typically cause pain in the center of the chest. It is also unusual for heart pain to persist for a week. So, pain in the left side of the chest for a week is atypical for heart disease. While this does not prove that it is not heart disease, it does mean that it is less likely.
Chest pain can also be due to conditions of the GI tract, such as acid reflux. This also will more often cause pain in the center of the chest, but can cause pain in either side.
If there are situations or actions that worsen or ease the pain, that can help to indicate the cause of the pain, but since none are present, the best that can be said is the overall likely conditions noted above.
At this point, there are a couple of options. The best option is to see your doctor for a proper evaluation. If you were trying to avoid seeing your doctor, then it may help to try to treat the most common cause of left sided chest pain by taking an over the counter anti-inflammatory medicine, such as naproxen. It also may help relieve musculoskeletal inflammation to apply moist heat to the chest. If these interventions help ease the pain, that would be evidence to indicate that it is from musculoskeletal inflammation.
If I can provide any additional information, please let me know.