I used to experience chest pains before but i never went to any hospitals or clinics to have it check and recently they came back. when i lay down on my side, it also hurts. at times, its hard to breathe. not sure if its serious or not and what to do?

Chest pain that is changed by lying on one side or the other, and with difficulty breathing needs evaluation. It is possible you may have an inflammation of the skin around the heart (pericarditis). There are other reasons for these symptoms; may also consider lung causes. Overall, should go in for evaluation promptly. Many times will need labs, echocardiogram, or chest xray.

With the description you have provided, it is unlikely that your pain is due to a heart problem. If it hurts only when you lie on the same side, it may be muskuloskeletal origin such as muscle or rib trauma. I recommend that you describe these symptoms to your doctor who will examine you and confirm whether or not it is musculoskeletal in origin and reassure you give you appropriate treatment.