Lump under kitty's ribs

I know I am worrying for no reason but if I press on my kitty's side near the end of her ribs i feel a lump. Should I be worried? I actually think it's like one of her organs or something. She thinks i'm retarded. She will be going to the vet soon for vaccinations and a check up I will point it out to him (he will probably think I'm crazy.) In the mean time I was wondering if you have any input.

Dosen't matter who thinks what - if you concerned it's good to have it checked - better safe than sorry.

No vet would ever put you down for being concerned about your cat's health.
I would take her in right away for an exam.

Better safe than sorry.