No, you do not NEED surgery or cortisone. As indicated above everyone should undergo at least 12 weeks of conservative management that includes a comprehensive and gradual strengthening program. Research shows that around 80% of people experience success with conservative management and that there is minimal difference in outcomes 5-years following surgery compared to those who didn’t have surgery.
In fact, This is really the only way to know if you actually NEED surgery. Surgery won’t fix the way you move or the strength of your muscles which is often the reason why you are in pain in the first place! Rehab and strengthening will fix this, and more often than not it will solve your problem and you can avoid surgery!
The same rules apply to cortisone. It isn’t targeted at helping improve your function, strength, and capacity around the shoulder. It can provide some symptomatic relief early on but the long term outcomes are no better than if you didn’t have it at all!