I had both Pfizer jabs, 19 days apart some 18 days ago. I had zero pain and no negative reactions both time, but I had prepared to take it easy the day after my 2nd jab. It was not necessary; I played golf in the afternoon.
All the doctors say Pfizer and Moderna are just as effective for patients. Now, I continue to mask, etc but I can now visit my kids this weekend in the same room for the first time in a year.
I should add that the Johnson & Johnson 1-shot vaccine results are confusing. If I did have a choice among the three, I would select Pfizer or Moderna. Getting a 2nd jab is no big deal.