Short answer: Yes provocation of pain is almost always essential to determine the cause of the symptoms, but relief of pain can be used to further support the hypothesis generated form the provocation of pain.
This weekend course reviewed knee pain, which can be tricky to properly diagnose, since multiple injuries can occur at once. PFPS is especially difficult as it is sometimes the cause of the knee pain and other times a symptom of another condition.
The picture below depicts “traditional” McConnell taping that can temporarily improve patellar tracking and decrease patient symptoms. If the patient is able to perform the previously painful functional test without pain the practitioner can say with increased confidence that the location of their knee pain is in the anterior compartment and not other structures such as the medial or lateral compartment.
Further assessment is necessary to determine the cause of the anterior knee pain, such as hip weakness that increased knee valgus or decreased quad strength/flexibility.