You could be having a stiff shoulder. Keep moving and using your shoulder in all daily activities. If it is temporary it will get better with movements.
If the stiffness has gone deeper it can lead to frozen shoulder so for that you must approach a good physiotherapist.
Next Steps
tendinitis or neck pain should be ruled out after thorough examination.
Health Tips
do not life heavy weight on your shoulder or in your hand until it is completely resolved.