How can I tell if my cat has a broken/fractured rib?

She's little over 5 months, and loves to climb on top of the fridge. A few days ago she fell behind it, and since then she's been anti-social, which is odd for her. She's hardly eating and when she moves she wobbles and limps. She lets us pet her (when she comes out from behind the couch) but only on the head. She cringes and mews a lot and just lays in her box behind the couch all day. She will still purr a little, but usually it's just a quiet meow of content. Our vet wants $91 to get her looked at, but I can't afford that until next month, which I fear may be too long to wait. If she does have a break or fracture, is there a home remedy that will help ease her discomfort?