Just to reiterate what Charm has said, you really need to start seeing a Physical Therapist. These issues are very common after a neck dissection and many of us have experienced this side effect.

Where physical exercise feels like the last thing you wish to do after this experience, let me assure you that it's one of the best things for you. Exercise is shown to be as effective as antidepressivants for treating depression. Due to brain chemistry the body feels more pain when in a depressed state (also very common after the cancer experience) so the physical exercise will also help with pain management.

Keep your head up, get into a physical therapist and keep plugging into these boards for advice and support

Eric