We took Midas to the dog park today and he was fine until he got home. He started favoring his back right leg, and it has gotten a little worse since then. He still is active and wants to play so he's not down and out about the situation. He is just very gentle with his back leg, sometimes lifting it up completely when he walks. We are thinking he probably strained a muscle or tendon but we can't be certain. What is the usual treatment/prognosis for a strain? We have been rubbing his leg frequently and are thinking about caging him so he has limited motion.