It's only been months not years, but neck/shoulder pain is the strongest "pain" symptom I have at 4.5 months post treatment, 7 months post selective neck dissection. There's stiffness turning it any way and shoulder pain from nerve damage.
Continual stretching and exercises for arm and shoulder help. Hopefully it will get better in time. I wouldn't want to be writing this 4 years for now, that's for sure!
Hope you get some relief!
Positive thoughts and prayers
"T"