1. Your Pillow - You sleep on it every night; plus you're often there for 33% of your life or more. Keep in mind that a good neck pillow loses its support after awhile too. The same goes for the mattress; if you're waking up everyday in pain and all the other variables are accounted for...
2. You Computer Screen - They have figured out it should be a certain distance and height etc... Don't even talk about screen type or tilt... Bottom line is that your neck and head should be fairly straight and one should look slightly down to the middle of the screen. Your feet should be firmly planted on the ground and lower arms should rest comfortably on the desk with hands on the keyboard.
3. Your Purse or Wallet - I've seen a lot of big wallets, try to tell me sitting on that and not throwing off your pelvis and lower spine. Remember, the entire spine connects and works as one; something way off kilter in the back is going to hit the neck eventually.
4. Your Chair - I had this computer chair once that wouldn't hold its height adjustment. For a couple day I just couldn't figure out whey I was looking up at the screen. Then one day I had neck pain after working on the computer. Needless to say, I very quickly got rid of that chair and have been neck pain free ever since.
5. Your phone - We don't necessarily hold our phones between our ear and shoulder anymore; that's eliminated some neck strains. But we do more often, look down to text, or read something...
6. Your Shoes - as I was saying, the whole spine works as one. Your feet are your base and inadequate footwear can be the reason for lots of pains.
7. Your Activities - do you have pain after a certain activity each time. The pain can be from that activity. It's kind of like sleep, if your pain is every morning then it's probably your pillow or mattress.
8. Bad Diet - this can be a bigger issue that you think. More and more people have different allergies or sensitivities than we might think. Is that going to cause us pain? It might. or it might not be directly, but you can bet it doesn't help.
Now you've got eight major causes of pain. Do your best to eliminate them if you can and you'll lead a much happier, pain-free life.