Come out with the answers for following questions.
1.Subluxation reason ?
2.Ranges and activity limitations ?
3.aggrevating and relieving factors of pain ?
Only then we can be clear with treatment.
Next Steps
consult with an orthopedic surgeon, one of the non surgical treatment is trying for manipulation but considering all the above history and ruling out red flags. Try and visit a manual physiotherapist.
Health Tips
1.Avoid lying on the involved side ,flat lying facing roof can be preferred keeping hand over head in long lever can be attempted provided it should not disturb your symptoms.
2.Cryotherapy may help you.
I will prefer figure of 8 or shoulder sling only after correcting the position else it may lead to improper alignment of that joint.