and tonight, for a moment i saw him chirping (sounded like he was trying to sing...) while he was fluffed with eyes closed, and looked like he was breathing hard...

He's nipping at everything; the bowls, the branches, the leaves, even his mom's tail!...
I'm new with baby finches, and sick finches in general, so I'm not entirely sure what the best method is for treating the little guy.
I have a heat lamp over his favorite perch, and he's always up there.