I sometime feels burning sensation and irritation in my penis after nocturnal ejaculation. Why is that and what the cure? Plz help I m worried

Possibly. Could be an infection if you are sexually active. If you are not circumcised, infection can sometimes occur at the skin or head of the penis. I'd get your doctor to take a look. Good luck.
Penile symptoms. If you have your symptoms only as you describe, and they are intermittent, occasional, and limited then it should not be a serious or dangerous condition, and you should monitor your symptoms. This can be normal. If you are having continuous or worsening symptoms, or you are having severe pain that does not go away, a fever, or continuous penile discharge, then you should see your doctor.