Thank you for the query.
Yes, umbilical hernia
can always be a reason of abdominal pain
. However, it can be also asymptomatic. Hernia is simply a hole in the abdominal wall. When the hole is small, but big enough to let intestine or omentum to get through, the contents of hernia gets squeezed and that is what hurts. So if in your belly button is a lump which hurts when you pres it, that can be the cause of your symptoms. If hernia is empty, it should not hurt at all.
If it is about ascites
, in most cases it does not hurt at all. The only way it can hurt, is when there is so much liquid inside your abdomen, that intestines gets squeezed and it can lead to intestine blockage. But it would be easily visible, and your abdomen would become unnaturally big, like with big ball inside.
Hope this will answer your questions.