1. Put your feet up on footstool. This will help keep your back up against the back of your chair preventing back and neck pain.
2. Get up and walk around every 20-30 minutes. Try leg lifts holding the back of your chair to get your blood flowing. And when you sit back down do some arm exercises before you pick up your needle and thread.
3. For shoulder comfort and or relief, roll up a washcloth, rubber band it and place it under your arm below the affected shoulder.