After you get done having sex is it possible , to have burning sensation when peeing without having a serious problem ?

Yes: You can have some irritation of the genital area after sex that goes away in a day or so. If it persists or worsens, it could be a sign of a urinary or vaginal infection and you should go to a clinic or doctor for an exam. Using a condom, even if you're on birth control can help prevent STDs . I encourage you to insist that your partner does this because people don't always have symptoms.