Despite taking Omeprazole everyday I still suffer with awful heartburn in the evenings and often wake up with it during the night.It goes right into my back and is very painful
I have the same problem.
I would go back to your doctor, mine changed my tablets to Lansoprazole and increased the dosage.
His advice that I found useful was prop up the bed and sleeping with lots of pillows. Not eating too late and avoid curries etc Keep a food diary and see what affects you.
Avoid tight waist bands.
Heartburn is a side effect of Parkinsons and the tablets for parkinsons.