At your age, such severe shoulder pain is unusual. It can be due to an injury or due to overuse (like in sports).
It would be better if you can post your Xrays and blood reports here.
Secondly, if you have received a steroid injection into your joint today and are having pain/burning sensation, don't worry. It is perfectly normal to experience pain/burning for the first 1 or 2 days after getting a steroid injection. The pain will subside in a couple of days.
Apply ice over the shoulder 5-6 times a day.
Next Steps
Take Tab Flexon (1 tablet after lunch and 1 tablet after dinner for 3 days) (if you are not allergic to the tablet and if your doctor has not given you any painkiller already)
AND
Take Tab Pantakind (40mg) (1 tablet before breakfast in the morning for 3 days)