I have been in chronic pain for about 18 years. Many different med combinations. Mainly methadone 40mg 3xday, and oxycodone 10 mg 3x day. Was 4 times a day but cut back due to chronic fatigue and fibromyalgia as well now. Was told it is common for chronic pain patients to develop fibromyalgia after long term chronic pain. I have always had acid reflux and GI sensitivities; hiatal hernia. However Over the last couple of months I feel sick to my stomach daily. I take generic Zantac 150mg 1 x day. I had forgot to fill it for a couple months, back about 3 moths ago, and was using up some pepcid i had laying around. After refilling it I started to feel better but then keep getting sicker. I am able to eat and sometimes it feels better to eat but then it gets worse; like I ate a handfull of glass and very gassy. I am wondering if I am building a tolerance to the methadone and where I cut out one dose of the oxycodone a day if I am experiencing some withdrawles from tolerance to methadone, 16 years now and dose has not been increased in about 2 years. I am 50 years old and they are trying not to increase the methadone too much where I will be on it for life. I have tried a bunch of other meds. I had good pain reduction with cymbalta and other antidepressants but I just can not tolerate them. They make me very sick! Any thoughts? Could this be due to all the meds i am taking bothering my stomach or tolerance buildup? Also take valium 10 mg at bed time. and metropolol for blood pressure and migraines. I know this is a no,no; but I do wake up in the night several times and sometimes will eat a couple of saltines with peanut butter to put something in my stomach and it does make me feel better to get back to sleep. I drink a good gallon of filtered water a day and 2 cups of coffee. I cut out soda about 2 years ago. I may have a soda once a month if not even less.