As an 18 year old with a healthy weight, diet, and exercise regiment, should I be concerned about left-side chest pains?

Yes, if you are experiencing any chest pains at all they should not be taken lightly and you should absolutely seek medical attention immediately. Chest pain can indicate a wide range of possible medical issues. It could be something simple, such as digestive problems or muscle soreness from exercising, but it could also be indicative of a much more serious heart condition or health-related problem.

If your chest pains are coming from the left side it could even point to a heart attack which often begins with slight discomfort in the center of the chest that progresses to pain on the left side and other symptoms like sweating and nausea may accompany this too. If you experience any of these symptoms along with your chest pain you need to go straight to an Emergency Room - don’t wait! Other conditions related to age that can cause severe discomfort in your chest include pericarditis (inflammation of tissue), pleurisy (inflammation of ribcage muscles), shingles (viral attack causing nerve inflammation) and more serious ones such as lung cancer, emphysema or pneumonia affecting that area. Of course these conditions are far less likely for someone who is healthy than many other causes but again whether minor or major - get checked out right away if there is anything off about your chest area while being aware what normal feels like when moving around normally so that anything changing is noticeable quickly.