My husband has had the first of Moderna; no real problems.
What were your ‘3 days’ like? First or second jab?
My wife, who didn’t get Covid, took the first one fine, but the second she didn’t get out of bet for 3 days. I got Covid, I was lazy/sleepy but never had pain that bad.
My boss, who had Covid, said he was “sicker than at any time in the last 25 years” and was out of work for 3 days, on the first shot. He described the pain as what “fibromyalgia” must feel like.
Your results may vary. My parents god 2 shots of Pfizer with no issues. Everyone else I know got Covid or Pfizer.