Terrible headache,sometimes lower back pain,gum hurts,sensitive teeth,speeding&slowing heartbeat,chest pain.no serious problem detected at the clinic?

Stress possibly.: Your symptoms are very vague and do not point to a single illness. If you are going through some kind of stressful situation in your life or hove anxiety, then that would cause all the symptoms. if not then you should go and see your regular physician for a complete checkup to rule out any proble. For the tooth and gum problem you should see a dentist.