--that any impingment of the spinal cord itself, as opposed to one of the foraminal nerve roots, may cause symptoms at multiple levels, depending on which tract is being compressed (or stretched). Symptoms can occur from the approximate level of the injury to any level lower.

So it is possible that physical therapy, especially if done brusquely, could have caused something to be moved enough to impinge something and cause symptoms at multiple levels. I imagine, though, that an MRI of the neck would likely show such an impingment if the symptoms came on that acutely--it would be similar to symptoms caused by a sudden trauma.