Thank you for using JustAnswer. I am happy to help you with your concern today.
First let me give you a little information on your neck. Your neck has 7 bones that are called vertebrae. Discs sit between each vertebrae. The discs in your neck are shock absorbing sacks that contain jelly like fluid. Think of them like a water balloon. If you just hold it it is round, if you push on it a little it flattens out but if you push too hard it ruptures. A disc bulge is like you pushing on the water balloon, where it flattens but does not burst. When the disc bulges it can press on a nerve. This is what a pinched nerve is, or it can bugle into the spinal canal this can cause spinal stenosis. This is also known as a herniated disc. You have joints on each vertebrae called facet joints. The nerves come from the middle of the vertebrae from the spinal cord.
Even though you do not recall an injury or strain to your neck, it sounds as if you have a pinched nerve in your neck. You do not have to have neck pain to have a pinched nerve.
A pinched nerve can present symptoms of arm pain, numbness/tingling and weakness that can begin at your neck or shoulder blade and radiate down your arm to your fingers.
The good news is a lot of the time these can correct themselves. Things you can do to help are rest the neck as much as possible. Take an anti-inflamatory medication on a regular basis. I suggest 400mg of ibuprofen three times a day with food (watch for stomach upset) Some basic neck stretches/exercises can also be beneficial. Here is a link for you. http://physicaltherapy.about.com/od/flexibilityexercises/ss/NeckStretches.htm
If after 2 weeks your symptoms do not improve or if the worsen before that then you should see your doctor to have a MRI of your neck done. Sometimes formal physical therapy is needed or steroid injections into the neck. Surgery is only needed in severe cases and should be a last resort.
If you have any further questions please let me know. I hope you get relief soon. Have a nice day.