The FDA says Pfizer’s Covid vaccine is safe and effective. But trial participants warn of intense symptoms after second shot

One Pfizer trial participant told CNBC that after the second shot, he woke up with chills, shaking so hard he cracked a tooth. "It hurt to even just lay in my bed sheet," he said. 

Others experienced headaches and fatigue.

The FDA said that while side effects of the Pfizer vaccine are common, there are "no specific safety concerns identified that would preclude issuance of an EUA."

https://www.cnbc.com/2020/12/08/pfizer-moderna-covid-vaccine-side-effects-trials.html