Yesterday morning i masterbated.same day at the night my sperm is ejaculated without masturbation. is this a problem?

No: You're fine. Especially when he's younger, a man may have a npcturnal emission even if he's had an ejaculation a few hours previously. A man often doesn't really empty his prostate and seminal vesicles. If someone starts telling you that this stuff is a problem, recognize someone who's trying to trouble you unnecessarily. If dad's a reasonable guy, maybe you can talk with him. Cheers.