Laura for sure it can be other things other than osteo. But if he is that much pain for that long is there no chance you can get him seen sooner? My Jack who is 9 was in severe pain with panting, nose dripping, non weight bearing etc and it was a very bad muscle injury in his shoulder. So try not to jump to conclusions yet. But his pain really does need to be addressed no matter what it is. and positive thought for you all.