Unfortunately, "I heard" doesn't cut the mustard as a medical opinion.
Being a little paranoid re side affects, causes thereof, how they correlate with various conditions, and the differences among the various vaccines I have been looking at around a half dozen articles a day.
In fact your description is flatly contradicted by every article that I have seen that discusses the subject.
And by "contradicted" I mean that the exact reverse of your "I heard" is what studies have reported.
Vaccination side affects among those previously affected are mild to non-existent.
Admittedly I've only seen your specific mentioned a few times. But if anything like your "I heard" had happened I have a hunch that it would have been mentioned in the couple of hundred articles and reports that
I've seen.
On the other hand, there are reports that Covid in India,& other areas of South Asia & of North Africa is significantly milder than in the US and Europe, with as little as a tenth or even a hundredth of deaths per reported cases of infection.
The best theory is that some mild similar virus previously occurred and gave relative immunity. We are talking about persons actually getting the disease, so it isn't just that deaths & serious occasions haven't been reported
Lack of reporting might explain the relative scarcity of cases (also true) but not how it affected persons who actually did come down with it & were studied.
The other major theory is that there are environmental factors. But that doesn't explain why India and not (for example) South Africa has many similar conditions but a high percentage of deaths.
Here's a
LINKedit: Spouse had two shots of Phizer & had zero reactions.

I've had one Moderna and had a sore arm.