Whenever i lay down or sit down a small bulge forms in my abdomen near my belly button. i never had sex so it shouldn't be pregnancy. what is it?

Normal: Um, guts, fat, intestines, bladder...Things that belong in abdomen and tend to be pushed forward when sit / bend.

Umbilical Hernia: Without examining you it sounds most like you have an umbilical hernia. If this aches or hurts you need to get this fixed.

Umbilical hernia: This sounds like an abdominal wall hernia near your umbilicus (belly button). Have your healthcare provider examine you and determine the cause.