Im only 22 and occasionally have a sharp pain around my heart, making it painful to inhale. then it goes away. what could be causing this?

Possible pleurisy: Pleurisy is inflammation of the lining of the lungs and chest (the pleura) that leads to chest pain (usually sharp) when you take a breath or cough. It is sometimes a sign of a serious medical condition, so if it persists you should see your doctor. If you have breathing difficulty or your skin turns blue, seek immediate medical care.

Muscular pain??: You are 22, unlikely to have a heart disease. It looks like you may have costochondritis/ muscular pain. However it is better checked by a cardiologist casting all doubts aside.

Chest wall pain: Most fleeting sharp pains in the chest are innocent and come from the muscles, ligaments, and nerves of the chest wall. Persistent sharp pain is not normal and can indicate pleurisy. This has a number of causes and you should seek medical attention if the pains are persistent.