Hello and Welcome to the Pain Management Forum. I am sorry to hear about your unusual symptoms.
I am not an expert and I think you need to consult your PCP.This could be your esphogus spasms due to the cold water... but that's just a guess.
I t does sound like this may be related to a gastrointestinal issue. I urge you to post your question in our GI Community as they are more focused in that area. Here's the link:
http://www.medhelp.org/forums/Gastroenterology/show/68
Please know that you are always welcome here but the GI community may have better suggestions for you.
Best of luck and please take care,
~Tuck