Shortness of breath, but only after swallowing

Hey there; I realise I've never posted on these forums before, so I thought I'd best give a heads-up! I've been suffering an awful problem for a good deal of time now, but nobody on my usual forums can suggest what is happening to me. As it feels remarkably like how people have described Asthma to me, I thought I'd describe my situation here. Any help you can offer would be much appreciated!

I've been suffering horrible shortness of breath/difficulty taking a deep inhaled breath recently, following 2 weeks of a very tight throat. The symptoms however ONLY strike whenever I swallow my own saliva, or water, and they get worse if the saliva is thick or if there isn't much of it. The more I swallow, the worse the symptoms get. The shortness of breath is leading to arm,head and chest pain, as well as me gasping and feeling like I will black out from head pressure/heart racing. Even alkaline water triggers it mere seconds after drinking it, but eating solid foods makes it subside for about 2 minutes at a time. After that I have enough saliva that I need to swallow again, and the shortness of breath returns.

I have doubts that this is anything to do with stress, because simply thinking about it doesn't bring it on, and NOT swallowing my thick spit/water/gaviscon/milk relieves it somewhat. Also I can wake up first thing in the morning and have no symptoms whatsoever, until I swallow my saliva for the first time. Then I struggle to inhale and feel increasingly worse from there, to the point of a feeling of fatigue. It's especially bad if my saliva is thick, because it feels like it gets stuck in my throat somewhere. I'm scared of passing out or damaging my body from lack of proper breathing-!

If anyone can help me pinpoint what is happening, I'd be very grateful..!