To Billylyne5
Thanks for starting this informative thread - I don't have much spare time (or brain energy) to search for answers to medical 'mysteries' so it's great when I come across a thread with lots of info. Hope you're making progress with your quest for a diagnosis. Hang in there.
To all who have posted thanks for the info, especially about AAG - even if some of it is beyond my level of medical-speak comprehension it is very useful and I will research further.

Specifically to Synnove re the "tightness in the chest" this sounds similar to a symptom (amongst many) I have been experiencing for a number of years. Some questions: Is it in the upper region of the chest - sort of lower oesophageal area? Does it come and go with no apparent reason or cause? Does the duration vary from hours to sometimes days or even weeks? Does the tightness at times feel like a burning choking that sometimes leaves you short of breath if you over exert yourself? Sorry for all the questions but it's a difficult symptom to describe. And also sorry for not being able to definitively attach the symptom to a specific diagnosis.
In my case I suspect that I may also have Sjogrens (as a secondary auto-immune condition to primary Addison's Disease (adrenal failure) - diagnosed 5 years ago this week). My father also had Sjogrens (secondary to RA) so I am familiar with some of the presenting symptoms. Unfortunately I'm in a country with a Public Health system so getting to see a specialist is difficult and if a test shows up negative - that's it! they stop looking! Have to keep pushing and looking for answers - won't go into all my other symptoms here but also suspecting some type of Peripheral Neuropathy. Had a confirmed bout of Trigeminal Neuralgia last year.
Also in regard to your other symptom "waking up at night with a rush like symptom that moves out over different body parts, accompanied by a sensation of warmth?" This sounds like it may be something called L'Hermite's Sign. It's a nerve spasm (bit like an electric shock) - often originating in the spine - it can be strong enough to wake someone from a deep sleep but goes quickly and doesn't normally leave any trace. If there are other symptoms with it eg weakness, or stroke signs definitely get it checked.
Hope this is of use to you and others.
at the same time