Hi! I hope I can give you some helpful information for Hondo. Was he doing something out of the ordinary in terms of running or jumping before he started limping? It may just be that now that he is a little bit older he can have some underlying arthritis
that he aggravated with overuse. If this is the case, then he will do better in the next 24 hours with some antiinflammatories. Baby aspirin is safe but is probably not strong enough for a dog his size. I wouldn't give him anything else tonight, but in the morning you can give him an adult buffered/coated aspirin. Make sure it is aspirin and not tylenol, motrin, advil, ibuprofen, etc. He can have this twice tomorrow and if it helps, then twice the following day. If the aspirin does not seem to help, then he will probably need to be seen for x rays. It is unlikely he has a broken bone
, unless there was some sort of obvious trauma. With a broken bone there would be a lot of swelling and he probably wouldn't use it at all. Hopefully it is just a soft tissue injury (sprain or strain) that will get better with rest and the aspirin. After 2 days of the aspirin, if he still needs something for the pain, then he should be switched to more of a "dog" antiinflammatory from the vet that he will tolerate better.
One thing we do get concerned about in large breed, older dogs, unfortunately, is a bone tumor. So if the soreness does not improve, an x ray will show what is going on. This is rare and most likely this is just more of arthritis acting up, but it is something you should be aware of. I hope this information helped. Let me know if you have any other questions!