This is totally normal. Vaccines produce an immune response. Immune responses can make you feel sick. Most if not all symptoms should subside in 24 - 48 hours. It tells you this in the papers they give you when you get the vaccine. Maybe try reading those instead of going straight to the internet.
Safety Report: Pfizer booster , San Mateo, CA, USA
This is totally normal. Vaccines produce an immune response. Immune responses can make you feel sick. Most if not all symptoms should subside in 24 - 48 hours. It tells you this in the papers they give you when you get the vaccine. Maybe try reading those instead of going straight to the internet.