That information i too less to actually identify the actual problem, the issue may be linked with some recent event like picking up heavy or throwing something even pulling. There is a need of thorough assessment before you get some advise and follow over it.
In certain cases common activities like warming shoulder (hotpack / hot water bottle) may lead to increase in swelling and cause more of damage, whereas icing / applying coldpack may be beneficial and in some cases the opposite is true along with some mobilisations and manual therapeutic techniques.
Next Steps
Look for nearest rehabilitation center for a thorough assessment and follow what is advised.
Health Tips
DO NOT JUST BLINDLY FOLLOW ANY ADVICE FROM ANYONE UNLESS AND UNTIL THEY HAVE ASSESSED YOU THOROUGHLY AND ARE MEDICAL PERSONNEL TO AVOID ANY COMPLICATIONS AND FURTHER DAMAGE SEEK UREGENT CONSULTATION. STAY HEALTHY