Those symptoms sound similar to most of mine in a flare up. I'm going through a round of them right now, usually at night or not long after a meal no matter what the food. I have tightness, blood pressure spikes, some tachycardia (despite B blocker), dizziness, chills/shakes, numbness and tingling in mostly feet and sometimes vision disturbances. Even after years of it I can still get freaked out if it catches me off guard. I also find I am more sensitive emotionally and frustrated by it. I had hoped after completing menopause it would improve as each phase lasting years seemed to be triggered by hormonal changes--puberty, pregnancy, menopause, etc. I have to do most of my own research too as my doctor is not very informed. He is referring me to a university for more help but referred me to a Dr. who doesn't even treat dysautonomia! Thus I am back on the web seeking direction. Our son has it too with a slightly different set of symptoms. Good luck to all of you striving for health with this disorder. :)
One of my symptoms is uncontrollable shivering. I feel like I'm having convulsions. Blood flowing to gut after eating is called sphanthic circulation. Blood flowing to legs after standing is POTS. One website recommends staying seated for an hour or two after dinner. I'm following the same path as you with lifestyle changes. I just started using a calorie tracker app to make sure I eat enough of the right nutrients. Please see my other recent postings for other aspects of what I have learned on my own. Doctors not helpful, even dismissive once they have ruled out everything else there's a test for. Please keep up your research and implementing everything you feel is helpful. No one else is going to help us I am afraid. Best wishes!
The chest pain, like any chest pain, ought to be evaluated by a doctor (perhaps a cardiologist).
Numbness in face or limbs is not at all atypical, and stems from the body shunting blood toward vital organs when blood pressure drops in upright position.
The changes in your hands including swelling, warmth, redness/purpleness or whiteness is a vascular symptom related to POTS, possibly even Raynaud's phenomenon and is also common.
Likewise with chills/shivering (or conversely, hot flashes). The only concerning thing I see here is the chest pain. Which, to be honest, is common in POTS, but still needs professional evaluation due to the possibility of serious issues as I'm sure you understand.
Best, H.