Thanks for your query.
Noted the history and understood your concerns.
Since you have acid reflux
and you are regurgitating everything or anything you eat, the causes need to be identified and rectified in the following ways since Prevacid is not helping you:
Get an Upper GI Endoscopy done.
Barium swallow and meal.
Clinical evaluation by a Gastroenterologist.
Addition of Domperidone
and antacids too.
Further management as per the reports of investigations like if there is achalasia, may need surgery.
Stricture esophagus may need dilatation.
If anything else the treatment would be directed as per the cause found.
Backache may be due to esophagitis
if in thoracic region.
If the the backache is low, may need an MRI of hte spine and muscles.
Take Percocet as advised along with muscle relaxer but see that they are not causing more regurgitation.
Take soft bland or better a liquid diet
Plenty of oral fluids to avoid dehydration