Hi Leena and Fran,
If your shouler pain is from the neck dissection, get yourself to a PT NOW. Don't wait to feel better unless you are so ill you can't get out of bed. The longer you let the drag on your shoulder affect your arm, the worst it will be.

For starters, the initial treatments will be like going for a massage. They wrap you in all these marvelous moist heated pads which feel so great you'll want to reset the timer. They then massage various areas on your back and shoulders, maybe neck and face also, especially if you are having lymph fluid build up. They will give you exercises to help you strengthen your muscles and get the shoulder back in proper position. The heat treatment alone is worth it. It greatly reduced my pain. Go for it and it's covered by insurance. Just make certain your PT is also the best massage therapist in town.

Take care,
Eileen