I've had neck issues for more than 20 years including left side weakness. Like most people, if you MRI a body part, you will find issues. They originally wanted to do fusion surgery but there was no way I was doing that. Over the years I made a lot of life style changes and it has gotten a lot better. Still acts up every once in a while but no where near as bad as it once did.

Also, most people don't realize this but your muscles play a big role in the pain. When you neck muscle are tense and knotted, they pull the cervical curve out of alignment. Best bet is to get daily neck massages if possible to keep those muscles relaxed. You can also look into the Brookstone Neck Massager. It actually works pretty good. Keep in mind some of the muscles that affect you neck are midway down the back. It's all connected.

Here are some other lifestyle changes I made:

1. Use a headset when on the phone and never hold the phone between your neck and shoulder.
2. Use 1 pillow instead of 2 so you head isn't jammed to the side
3. Limit or eliminate neck exercises such as shrugs and upright rows
4. Try to sleep on your back with a pillow under your neck to keep your cervical curve in alignment
5. Sounds silly but make a conscious effort to work on your posture. Hold you head up high instead of hanging it and keep your shoulders dropped especially in the Winter when it's cold.

I no longer have any weakness and that's pretty much all I do.