What do your anecdotes matter? The original clinical trial for Pfizer mRNA vaccine has 20% of the treated group (younger than 55) reporting moderate or worse side effects. We don't know how long these last because they did not release any data on that. Could be days, could be a year for some people. for all I know.
20% is _not_ the same as the general and extremely broad statement made by GP. Making such a broad statement is either ignorant or disingenuous. I'll let you decide which
https://www.nejm.org/doi/full/10.1056/NEJMoa2034577