You need to get back to your doctor. You may have a pinched nerve in the neck area.
If you are still experiencing pain when you breathe in, you do need to get your lungs examined.
Wear a scarf around your neck to keep it warm and avoid draughts. You may benefit from gentle massage and seeing a physiotherapist.
May even be worth getting an xray done to find out if there is any osteoarthritis in that area that is causing the problem and also find out whether it is only a muscular problem.
Also look at how you do things to find out what has brought this on. For example, lifting, doing repetitive jobs that put a strain on your neck and shoulder, sitting in a draught, doing gym work without first doing warm ups.