Answer

Hi, thanks for your question. The symptoms you are describing are most consistent with back pain. In small breed dogs, when we see reduced activity, stiffness, and arched back, and reluctance to eat/drink, but no vomiting/diarrhea, we are usually suspicious of back or neck pain.

The most common reason for back pain / neck pain in a dog is Intervertebral Disc Disease, which is a condition where the cartilage discs between the vertebrae can bulge and put pressure on the spinal cord, leading to pain, muscle spasms, and stiffness.

You will need to have him seen by a veterinarian, in order to have a thorough physical exam, and possibly some x-rays. Then, as long as nothing else is identified on x-rays, some pain medicine, muscle relaxants, and anti-inflammatories may be prescribed, along with strict rest for 2 to 3 weeks. This is usually effective for most cases like this.