Dog limping

She randomly jus started limping favoring her front right leg. when i squeeze her paw she doesnt mind it or when i press around her joints, but when i try to straighten it out she barks. I am hoping this is just a sprain, shes still happy wagging her tail being herself, jus on three legs.

He’s been doing it for about 2 weeks now, he doesnt seem to be in pain and still runs and he doesn’t limp for long just when he first gets up and it always his left leg, so I dont think its because his leg is falling asleep, he is eating fine(he’s a hog lol) drinking fine, he plays with our other dog all day long, they play really hard, I’ve been trying to reduce his exsersersise and the running and hopping around, he is only 2 years old he’s a rottie/lab mix, I know rotties have problems with their joints-he’s been on glucosomine for about 6 months just incase kind of thing, we are going to see the vet tomorrow, but I just wanted to see if anyone has any thoughts? I thought it was muscle sprain, but its been over 2.5 weeks