thanks for your query at HCM
your diagnosed with gerd and barretts oesophagitis, the pain and tightness below sternum are due to above conditions.chronic gerd
will result in barretts .
these both can cause severe pain
you should be concerned with non progression of barretts because it has chances to grow in to cancer in future.
you should be on regular endoscopy
and biopsy for ruling out progression of the disease.
20 mg twice daily half hour before meals this will decrease reflux and pain asscoiated with it.
hope this is helpful