Sorry to hear that your shoulder still hurts after 3 months.
That may mean that something may have been damaged inside the shoulder joint. It could be a tendon, or part of the capsule that supports the shoulder joint. Having pain for 3 months is not normal.
I would advise you to see a doctor/orthopaedic surgeon. A thorough shoulder examination, followed by an MRI scan is usually necessary. Management of the problem would then be dependent on what the pathology is.
Hope this helps,
Dr Sean Ng