Penis will have a stiging sensation shortly after ejaculation sometimes happens for a few seconds then goes away. It doesn't hurt peeing either?

Painful ejaculation. Painful ejaculation can be caused by a number of things. Inflammation anywhere along the reproductive tract, including the urethra may cause painful ejaculation. Since you are young, I would recommend getting tested for infectious causes. Your doctor would be able to check your prostate. Also, look into how to perform testicular self-exam.