I Have Been Diagnosed With GERD (three Plus Years Ago),

I have been diagnosed with GERD (three plus years ago), but lately I have pain in my upper chest (sternum?) with accompanying belching and burping. This has become more severe in the last couple of months and lasts all day and into the night. OTC drugs do not help. I took omeprazole for three years, but I recently stopped taking it because it didn't seem to be helping much, if at all.