34 weeks pregnant onset of sharp back and chest pain upon deep breaths. when sit down after being active chest and back throbs for short while . negative ecg , negative vq lung scan and negative echo . do have awful acid reflux and low iron? cause?

Chest pain provoked by a deep breath is seen in pleurisy, pneumonia, pulmonary embolism, pinched rib cage nerve or muscle that runs between 2 ribs & occasionally in pericarditis. In your case, with negative VQ scan,EKG & echocardiogram, I favor a rib cage cause. A chest X-Ray would be worthwhile only if you have cough& fever. Avoid stress on rib cage. Get reexamined if chest distress persists.