Thanks for posting your query.
Usually such pains are elicited by sprain
& strain, trauma, bad posture,inflammation of muscles or tendons, pinched nerves or bony spurs. You should avoid the movements that cause pain and rest your shoulder for few days before starting routine activities. Icing the pain area for 15 to 20 min , 3 time daily for 3 days can reduce pain, ibuprofen
you are taking is also helpful.Physical therapy
is useful and you should use a sling or shoulder immobilizer. In some cases corticosteroid shots are also needed.
To prevent shoulder pain
in future you should exercise daily, if you are obese then reduce your weight, take healthy diet and add vitamin C
and bioflavonoids to diet.
You should get X-ray and MRI to get detailed picture.
Hope it helps.