3 month old kitten with swollen chest

Question
My 3 month old kitten has some swelling in her chest.  Its soft and it doesn't seem to hurt her.  She was running around a lot today knocking things over. We also have a small wooden board that keeps the dogs out of our family room so its possible that she could have hit that while jumping over.. But I'm panicked because I looked up kitten with swollen chest online and all I am finding is information about FIV.  she has no other symptoms.. She's very rambunctious and playful.  She's been eating, using the litter box and been her normal self.  

Also she had her second set of shots yesterday if that matters..

Answer
This swelling could be some fluid from her getting her vaccinations. Not fluid from the actual vaccination, but some tissue swelling that has traveled downward as gravity pulls fluid down from the top.

I don't know where she got her vaccination but you should call the vets on Monday and ask them.
The other possibility (but not likely) is that she has a small abscess growing on her chest from a wound. She could also have swelling, as you said, from a bump-but that would have to be a hard bump to cause that.
FIV usually starts in the belly, not the chest area. I am guessing you mean the spot between her front legs? Most people consider that the chest area. If not, and you mean on her side by her shoulder blades-then my guess is the vaccination caused some swelling.

Just watch it and call the vet on Monday if it is worse or still there. Do NOT give her any aspirin or any thing for it. These drugs are deadly to cats.

Let me know if it goes down or what the vet says.