It is my turn to get the Covid-19 vaccine because I am a member of civil defense in my country.

All of Korean males shouldhave to/must work in the military service for more than one year, doand do the reserve forces training for about eight years andto become a member of civil defense.

These members can get the vaccine from today.

You can say: “This group can get vaccinated/get the vaccine from today”. Yours isn’t incorrect either though.

It stings more than the flu vaccine, I guess/I felt like.

Some people said that the body temperature climbs 7 hours later afteran raise up after about 7 hours of getting vaccinated, so I am checking my condition carefully.

I hope, my immune system will adjust with the vaccine soon.