Most probably it would be sprain,
For now what you have to do is:-
Give rest to your shoulder, by using arm sling.
Hot fomentation( सिकाई) after applying a anti inflammatory gel.
Take some NSAIDS and continue for 5 days.
If the condition remains same , visit Doctor.
Next Steps
If improvement, continue treatment and fomenting.
Health Tips
Avoid lifting heavy weights and hard labour.