What Causes Severe Pain In The Left Shoulder?

Hello there, i ve had problems with both of my shoulders, at the tip of the front of the shoulder to be exact, my left shoulder hurts more, so i visited an orthopedic and he gave me anti inflammatories; but they didn t seem to work, the second time he gave me stronger anti inflammatories and a gel that containd 0.5 mg of piroxicam, it didn t work either, the last time i visited him he said that i have one more solution befor i could have a surgery, he gave me a cortisone shot in my left shoulder, at first there were some moves that i could not do, and it hurted so much; after the cortisone shot i ve seen a big improvement, i ve gained my range of motion and it doesnt hurt as bad, in conclusion i think my shoulder have been healed almost 90% and it does not hurt all the time like it used to, and when it hurts it does not hurt that bad its almost like a pinch befor the cortisone shot it was almost like a knife was going through my shoulder, so my question is, do i still have to have a surgery because it did not heal 100% ? thanks for answering.