I have this symptom as well pretty much all the time. I know I have acid reflux but this may be caused by LPR which is similar except it involves the higher sphincter valve in the esophogus as opposed to the lower one. Not sure if this is related or caused by FM or other but I also have frequent neck pain, its as if my muscles in the neck are sore from holding my head up all day and is worse at night. My jaw aches to especially if I sit with my ching resting on my fists for any period, like when I am my computer and since computers are my trade this is pretty annoying. Not sure if you have these as well but I definitely have yours. I think for me caffeine and sugar are triggers for my reflux.