When I have a stressful day, why do I have more neck and back pain?
When stressed, people tend to contract their muscles. For example, people tend to elevate their shoulders toward their ears when stressed, thus causing increased tightness at the muscle on top of the shoulder (Upper Trapezius). This leads to increased muscle tightness, which in turn can cause more pain.
Regarding physical therapy of your neck and back. If you continue to have increased stress in your life while receiving physical therapy, this will lengthen the amount of time it takes to have a successful treatment outcome. During therapy, the therapist will provide you with techniques to prevent further tightening of your neck and back musculature.