Call your doctor if you are not having symptoms, or go to the emergency room if you are at this point in time. They will give you an ECG (a.k.a. EKG). It is a quick, painless test where they attach electrodes to your chest that measure the electrical activity to your heart. Chest pain as you describe is usually associated with ischemia (decreased blood flow) to the heart muscle itself. The ECG will show if there is damage to the heart muscle existing now and if the heart muscle is currently experiencing ischemia. There are several different ways to treat the porblem, from medications to possible surgical procedures. Don’t be afraid. It is treatable. It is better to go now for preventative medicine or antithrombic medications to treat a blockage than to wait for a major MI. Sometimes young people have high blood pressure and high cholesterol for years without knowing it, or a dysrhythmia (such as an atrial fibrillation) may be undiagnosed and allow blood to clot in the atria of the heart. This condition is treatable with medication.
A potassium difficiency may cause both heart symptoms and restless leg syndrome. A basic metabolic panel ordered by your physician or done at the hospital will show if this is the problem and can be treated by IV or oral suppliments. (IV first since you are experienceing symptoms).

To me you need to see a doctor and the sooner the better.