Odd mass on stomach

My cat is 3 years old and has a clean bill of health. She had her yearly checkup a few months ago. A couple years ago I noticed a lump on her stomach but it was hard to find after so I assumed I imagined it. My friend noticed it a couple weeks ago and you can only feel it when she's in a certain position on her back. It doesn't seem to cause her pain and it's almost an L shape. It's not hard, its soft and right under the skin. It is located on her abdomen just to the right of the center. I dont have much money right now, so I can't afford xrays. I'm wondering if this is something I should be really concerned about, and what it possible could be. Thanks.

may I ask you, how could you identify it was in the stomach? maybe, it is a soft hair ball that is so common in cats.
   
I suggest you to use Cat Malt. it helps your cat to get rid of it.

Has the vet looked at this mass? It's possible an x-ray will be called for.