cj asks a good question. Did this start after you went on one of these meds? Do you have any other symptoms? Heartburn? Does it happen after you eat?
It could be one of the meds, but it also may be something like GERD. You can try a few different things. If you take your meds on an empty stomach, try taking them with food, and vice versa. If this happens a lot at night, when lying down, that points more to a GERD likelihood. In addition to seeing your doctor, don't eat for a few hours before bed, and skip any spicy or heavy meals before going to sleep...also alcohol.
I would suggest mentioning it to your doctor to try to sort it out.
Has this always happened when you take this medication? Have you changed your diet? I know when I was drinking a lot of soda or carbonated beverages(especially if I took the meds with it), I could taste anything that was put into my stomach recently.