hello hello hello!! i have such similar symptoms. wow!! i totally get that thing where it goes up. i get tension in my chest, then throat, and get a headache. if i don't pee or poop right away wheni get the urge i get a headache immediately. but all goes away temporarily when i pee. i can also get severe tenision in my arms and legs when having these issues.nothings really helped me with this so far. it waxes and wanes with intensity too - so i bet it won't be this intense for you for long. i think our problem has to do with all the nerves getting crazy signals and it all being connected. sometimes i fart just a little and my all over body tension is relieved. what felt like a GREAT pressure is gone wiht just a little fart. sometimes the pressure signals that i have a lot of gas inside. so its so confusing. but i think the bottom line is our nerves are OVER responding.have you tried acacia root (fiber)?have you tried Paxil?have you tried Levsin?have you tried low carb?those were the things that helped me most.also, do you get worse when you've had a bowel movement - like the bm makes you feel better temporarily, but you KNOW after that empty feeling is going to come TERRIBLE pressure - usually in the evening or next day. i almost do best slightly constipated b/c it seems to even things out for me.