I have this tingling sensation in my belly button for past few days like it's being tickled from inside. what might be causing this? is it anything serious that needs to checked out in hospital?

It is possible you have a small umbilical hernia and the bowel is going inside and the bubbling in the bowels is what you are feeling. If it is very small the danger is very little because not enough of the bowel would go inside. The danger is when enough of the bowel goes inside and gets strangulated inside because it cannot come out and that could block blood supply and acute changes.

Infestations with Intestinal parasites like Ascaris, comes to mind. A visit with the PCP is appropriate and Stool test for Ova and Parasites among other studies should be considered.