How do u tell the differences between normal chest,arms, and back pains and pains that r heart related or life threatening?when should u see a doctor?

Good question: You should discuss these symptoms at least once with your doctor if they are bothersome to you. When these pains are also associated with shortness of breath, fatigue, profuse sweating, nausea, dizziness, searing back pain, exertion, a sense of impending doom and other worsening feelings, you should seek immediate attention. There are important conditions that are in between - see your doctor!