Regarding acid reflux, I suggest you carefully check out http://www.naturesplatform.com, http://www.inclinedbedtherapy.com and thoroughly read "why stomach acid is good for you" by Wright and Lenard.

Regarding the Wim Hof method, I advise you to be cautious, it is very nice to hear that it helped you, but it is supposed to carry risks as well, found this in the internet: