I took covaxin yesterday . today i got 100 fever. my body is paining. i am having legs and back pain from many days. i took fever medicine but still my fever is 100 till now. what to do ?

We do not have much experience with Covaxin but fever of 100 F is not worrisome. You said you have had body pain for days even before the vaccine. Is there any chance you had had contracted Covid-19 before the vaccine or you always have leg and back pain? In summary, you should not worry much about T of 100. Usually, the vaccination side effect will be over after 2-3 days.