Greetings, sorry about the pain. You are suffering from an impingement of the shoulder which needs physio intervention. As a home care ice the area thrice a day and use a sling to support shoulder so that arm weight is well supported by sling.
Next Steps
see a physio near you and get trigger point release plus myofascial release done. after 2 weeks of treatment you will be taught exercise to strengthen shoulder. in 4 weeks you should return to normal activities without any issues
Health Tips
try not to sleep on affected side and rest the shoulder as much as possible.