I would find it very stressful to spend 3 hours trying to use an iPhone. The visual struggles of trying to process such a small screen would be too much for me.

Maybe you will do better staying off it for a while.

Have you done any icing of your neck? Sounds like you may have inflammation that could effect your blood flow to your brain or such.

Do you have access to a physical therapist who can try to work on your upper back and neck? I used to have trouble with my left arm with tremors and numbness. My PT was able to help me get improvement to C-6 to T1.

It took quite a while few treatments to get stability. My upper neck has never healed to last. It gets out of joint from time to time. I'll get sore behind my ear and may need to ice my upper neck for a while.