my pitbull dalmation mix(spelt wrng i knw) has problems walking yelps and crys.......?

[Bri James]

okay she sleeps on the couch an beds but a few days ago i got into bed and laid down by her and i touched her hip and she yelped out then stopped the next morning she looked fine walking running braking normal then at nite time she was on the bed as she started 2 yelp and cry and wine i got her down and she moved very slowly i brought her out 2 where i culd c her she started shaking in my arms and wine a little but i push every part of her legs back bone and she doesn't cry or react unless she's laying down but now its getting worst she became 2 where she hardly ever gets off the bed and when she does she doesn't look up at me calling her she backs far away and sits where she can see me she walks with a little limp but now she wont get off the bed and if she does i have 2 help her up & down if i come into the room and talk 2 her she wont move she just wags her tail when i feed her i have to put the food in my hand because she has problems eating out of a bole or plate im afraid she has a brain tumor does anyone knw whats wrng with her? she is 5yrs old btw.