It might possibility be panosteitis. It usually comes on suddenly without any apparent injury, and can come and go. It can be very painful for the dog with limping and and when the affected area is squeezed they some definate signs of pain. At least our Bassets did. We have had two Bassets that have had this and crate rest was prescribed by our vet.
Here is some info. on it from the internet:
Panosteitis is a spontaneously occurring lameness that usually occursin large breed dogs. Panosteitis is most common in large breed dogs between 6 and 18 months of age. Occasionally, middle-aged German Shepherds will have a bout of panosteitis. It affects dogs worldwide and has been recognized and studied since the 1950's. Male dogs are much more likely to get panosteitis then females. There is a higher incidence in several breeds including German Shepherds, Great Danes, Doberman Pinschers, Golden Retrievers, Labrador Retrievers, Rottweilers, and Basset Hounds.
What causes panosteitis?
Affected dogs are usually in the 5 to 14 month age range and male dogs are more commonly infected than female dogs. The disease has been reported in dogs as young as 2 months and can occur in young mature dogs. The lameness tends to occur very suddenly, usually without a history of trauma or excessiveexercise. In most cases one or the other front leg is affected first and then the problem tends to move around, making it appear that the lamenessis shifting from leg to leg. There are often periods of improvement and worsening of the symptoms in a cyclic manner. This makes evaluation oftreatment difficult since many dogs will spontaneously recover with or without treatment and then relapse.
X-rays usually reveal that the bones have greater density than is normallyfound. If pressure is applied over the long bones, pain is usually present.The X-ray signs do not always match the clinical signs.
I hope Sookie gets better quickly.