normal?

baby got 4 month shots yesterday. he’s been sleeping a lot since. just noticed one of the two sites is red. he’s been really fussy. last night he woke up really frequently and was screaming like he was in pain. normally he just wakes up and whines a little and tosses around looking for a boob. not sure if these are pretty normal? i know someone who’s baby just passed away at only a month younger than mine so i’m also really paranoid 😢