About 9 Months Ago I Was Lifting A Large Tv

about 9 months ago I was lifting a large tv with a a friend and It may sound funny but I heard a ripping sound followed by a sharp pain in my upper arm/shoulder this pain the next day my shoulder had reduced movement and I was sent to a see a doctor at hospital after several appointment he gave me an injection into the shoulder joint which did free up movement and discharged me but I still have pain in the shoulder and upper arm which feels like more muscle/tendon pain than joint I have gone back to my doctor who has now said he wont,s to give me another injection into the shoulder. would this help with the muscle/tendon pain I am having