What Causes Severe Heartburn After Insertion Of Esophageal Stent?

I had an esophageal stent inserted three days ago, due to cancer making it very difficult to swallow. I can swallow much easier now, but I suffer from a lot of pain like severe heartburn. It is especially bad a few hours after going to bed. I followed the doctor s recommendation of inclining my bed, but at the moment it is only six inches higher at the head. I can make it higher easier enough. I m taking an antacid and low dose hydrocodone to alleviate the pain, which works to a certain extent. Is the pain due to my diet? I m hardly eating anything, but I do have a cup of coffee in the morning.