A strain is a stretched or torn muscle or tendon.
This can happen in your neck for a variety of reasons, including spending too much time hunched over your computer or sleeping with your neck at an odd angle.
It can also be due to a simple movement like craning your neck under the sofa to get the dust bunnies.
Many people think strains only occur after intense physical activity, but they typically happen after normal, insignificant activities.
Don't be embarrassed if you strain your neck while reading in bed or doing the dishes. It happens to the best of us.
Treatment for a strain involves resting your neck as best as you can, or ice the area every 15 to 20 minutes every two or three hours until the pain stops.
That's usually all it takes, and you'll feel better within days or weeks.