do you have any blood pressure problems ever?
Due to the sudden and short-length of these episodes it may (out of the highest concerning possibility) represent an abrupt increase in your blood pressure (which can explain all your symptoms).
There is something called a pheochromocytoma which can cause these instantaneous (and either short lived in some people or lasting hours in other people) changes in blood pressure, palpitations, shortness of breath.
It happens because a growth of the adrenal gland releases a load of hormones all at once.
This is easily diagnosable with a blood test.
So it is dangerous to you (but completely treatable by surgery) and easily ruled out, so therefore it would be the first thing I would suggest getting worked up.
At the same time they can check your thyroid hormone levels, however that typically causes a continuous elevation in blood pressure and heat intolerance. A simple blood test checks for this as well, but it doesn't exactly fit with your symptoms
Your primary care physician can order both of these tests.
They should also check your blood pressure (this can be normal in some people with a pheochromocytoma) so a normal measurement doesn't rule these things out.
They will also have to do a urine test in tandem with the blood test
Please avoid drinking beer, wine or eating cheeses until you have this fully evaluated as those foods can exacerbate the symptoms and frequency of attacks if it is a pheochromocytoma
They will also do an ekg, standard blood panel just to round things out, but a pheochromocytoma is my primary suspicion/concern
does this sound good to you?
Have I provided good service? Otherwise I will discuss this with you more.