I have not personaly had the trouble you have but my youngest daughter was born with really bad reflux. I know that this is not the same thing as you but she was on alot of meds that you use as well like nexum or previced as well as mylanta. I know that these meds can take upto a month befor they start to work effectively and it can be trail and error with which meds work for you.
As well I know they told me with my daughter that eating 5 smaller meals a day and not eating late at night works better for all the acid. Watch out for trigger foods as well that will make it worse for you at night. Your gastro should have givin you a menu of these food as well as one with good foods that help out as well and if not you should ask him/her about it.
I am not a doctor just giving you my experence with gastro problems and you should ask you doctor about all these questions you have. I would think that pain meds would make your condition worse because alot of them can cause upset stomach, I know mine do.
Hope all goes well