My Dog Has A Hurt Leg Somehow?

Okay so today i came home and i picked up my dog, shes a cockapoo, and she cried when i like lifted under her arm pits. and she walks fine its just like she goes up the stairs slow and cant really jump like on the couch and stuff. So i was thinking like idk that it was like a sore muscle or something. Shes paper trained and doesnt go outside. We have a huskee and they get in fights once and a while and idk maybe he like stepped on her or something. Did any of u guys dogs ever act like this? Will she be ok with some rest? She walks and stuff fine its just when she has to lift her self pretty much, so i think its her muscle like maybe she fell down the stairs idk. What do you think?