What does my dog have and what is a natural way to cure it

Now, if you're absolutely certain there are no injuries and fairly certain it's not arthritis or depletion (which, without a vet visit you really can't be completely certain) then there are other options. Constipation can cause bowel discomfort in the hind end which could, in extreme cases, cause tenderness in the back by default. In other words. "dude I hurt just keep your hands off". Colic is another possibility but truly there are too many to name...including heart worm or parvo.

To check for joint pain you can have the dog stand on four legs, then pick up one leg GENTLY and try to kind of slowly move it back and forth. You really shouldn't do this yourself though, it's like moving an accident victim who could have a neck injury. But if you're insistent and stubborn ... place one hand on the front of the joint, cradel the leg with the other hand while moving it and move it GENTLY and don't move it very far in either direction. If your dog increases in distress such as whining or an attempt to get away or even bite you ... it could be a sign of joint pain. If the pain seems to be the same regardless, however, then you should probably consider that's it's a viral issue.

For joint pain you can give your dog a baby aspirine for the pain, one pill for dogs 10 lbs and under, 2 for over 10 lbs and no more than 2 in a 4 hour period. A heating pad will also help and try to keep your dog from getting up and moving around. Treat it like a football injury. However this is just a temporary fix to help with the pain, the bigger problem such as dislocated joints or depletion are not fix-a-ble on your own and your dog needs to see a vet.