There are multiple of reasons that cause pain between shoulder and neck ie - Rotator cuff tear , Wroung Posture and sleeping position ,
You're occupation.. over exertion activities can cause or trigger the strains and sprains in that localised area.
Stretching exercises & different techniques based on science of Physiotherapy can help you out in overcoming the pain be releasing the compressed nerve ( Pinched nerve ) if it's a radiating pain.
Next Steps
Start being concious and aware about what is triggering your pain ...after you figure out that one reason.. start working on that correction of your posture, sleeping pattern if it's either of them.
See the Physiotherapist or the correct doctor available in your environment to get the correct diagnosis and to get the right treatment.