So I noticed this hard-ish lump on the right side of my rabbits belly (it’s under her skin). I first noticed it about a month ago or less when she had tried to eat a gift from my friend and was giving her a massage. Ironically, she had eaten the head of a clay rabbit my friend had given made and being the scared parent I am I took every precaution to make sure she was okay. And she was. So, as I was massaging her, I noticed a lump that was maybe the size of a small, sort of flattened ping ball? I don’t really know how to describe it other than that. 

Anyway I marked it off as an organ. But now that I’m thinking about it, it’s might be a tumor or something. She’s acting totally fine, eating fine, doesn’t seem to be in pain, and is pooping as often as usual. Is it an organ, or something worse that I should bring her to the vet for? Help me out anyone?