lump question

[Linda Wallace]

I was petting Mocha (spayed, 2 yrs old) this morning and felt a lump on her torso. Actually it was just behind her front left leg, but underneath her - I guess that would still be considered her stomach area? It was right where the black and white fur meets. It's about an inch away from a nipple. Anyway, I've made an appointment for the vet today, but unfortunately the only one who was available seems to be very laid back about a lot of things, so I don't know if I'm going to trust his opinion.

My question is, are there any things I can do to try to determine if it's a harmless lump or something more serious? It felt kind of hard, it's not discolored and there's nothing in the surface of the skin to indicate that there should be a lump there. She's been acting and eating normally.

Thanks in advance for any advice!!

Linda & Mocha & Latte
Blacksburg VA