Apollo, who is 18 weeks old, started limping yesterday. I noticed it when I picked him up from doggie daycare....since he's my baby and my first boxer...I'm freaking out! He jumps into the car but limps when he walks....could this be a sore muscle or could this be something with his joint? Don't boxers have hip problems? Any ideas on what it could be or any insight would be greatly appreciated. He normally doesn't jump off anything without assistance and I haven't seen him fall of anything either.