What Causes Severe Heartburn At Night?

I get severe heartburn at night, especially after getting into bed. Have seen a gastro and she prescribed Pantoprazole 40 mg each morning 1/2 hour before breakfast, no eating or drinking after 6 pm and 2 150 Zantac at night. It helped at first but now I am waking up with severe heartburn, rattling and congestion in my throat an inability to swallow. After sitting up for an hour or so, it subsides but every morning I wake with throat congestion and coughing. Should I continue with the gastro or see an internist or ENT? No other health problems or meds except 10 mg of Crestor daily. I am 68 and no other health probs. Thanks