Where did you put the Dexcom? Arm, stomach, someplace else?
Which model Dexcom are you using. Is the the G5?
No - it is not normal for the Dexcom to be hurting the day after it is inserted.
I agree with Firenza but rather than waiting for another day, would suggest to call Dexcom Technical Support now. They always have people on the phone ready to help no matter the day or time. You don’t even have to have a real problem to call them. For just a question even you can call them.
Dexcom Technical Support: