Hello, I Have Terrible Chest Pain In My Left Side,

Hello,

I have terrible chest pain in my left side, I've had it before and been to the doctor's here and they couldn't really find a cure, saying it was probably a muscle spasm caused by stress. It seems to keep reoccurring randomly; it's a sharp pain, just below the breast, but it seems to also move upwards to my neck and my shoulders at its worst points. It hurts to breathe in at the fullest point. It really feels debilitating when it strikes, and makes sitting or lying down very painful. Please advise on whether I should be worried or just be reassured that it is just a muscle spasm in the chest. Thank you for your help, Helen