Joint pains can naturally heal if your pet is in its growing lifestage and capable of reproducing the damaged tissues rapidly. Actually, pets in this age do not usually get joint pains unless it is due to injury. Hence, to be realistic we would not believe your pet can rapidly heal himself of the joint pains after getting old. Also, your pet will need a rich diet and rehabilitation to cure arthritis if not with any joint meds for dogs. In the end, you will have to go with some supplements of a kind or another to heal the joint pain of your pet. That said, still, there are possibilities that your pet will need a few weeks to months to heal depending on the severity of his joint pain and rate of healing.