Anxiety maybe???
It can cause some strong sensations.

Were you stressed or worried about anything at all when these feelings happened?

Is it only in your throat & chest, nothing noticeable in the neck or shoulders?

There is a nerve that goes around the ribcage.... now I recall the name of it -inter coastal.
I and some others with thoracic outlet syndrome {TOS} have had severe spasms that affected our breathing/chest, felt like our hearts were palpating strangely, and some other oddball things.

Some also went to ER to be checked for heart problems.
I would have but I had read about others experiencing the same symptoms only to find out is was spasms & nerve related.

I realized mine was muscle related as dh & I had just finished doing a week of concrete work.

we have an anxiety forum here if you would like to read up on it -
http://neurotalk.psychcentral.com/forum50.html

our TOS forum is here if you want to read more about it-
http://neurotalk.psychcentral.com/forum24.html