I got the vaccine long before getting Covid (about a year before), and have had palpitations ("butterflies") since the vaccine.

Are the two related? No idea. But it illustrates the fallacy of relying on anecdote. For anything.

That said: we know that the vaccine causes myocarditis in younger men, and the rate is at least in 1 in 5000, and quite probably higher than that [1]. A recent study of Thai boys suggested a much higher rate, on the order of 1 in 100 [2]:

[1] https://anishkokamd.substack.com/p/vaccine-myocarditis-updat...

[2] https://twitter.com/anish_koka/status/1560617943762878464