What should i expect during physical therapy for upper trapezius pain?

Less pain: If you are concerned about the effect of physical therapy, then you should have your pain diminished and range of motion restored. As far as modalities that will be used, i suspect you will have massage, stretching, heat/ice application, ultrasound, iontophoresis, may be traction. It all depends on the physical therapist, his experience and comfort level.

Varies: This will vary depending on you therapist. They will likely concentrate on your neck as most trapezial pain comes from cervical pathology. Massage, deep heating, ultrasound, muscle stim, stretching & strengthening exercises, and traction are all common.