The rotator cuff is one muscle:

The rotator cuff is actually made up of 4 muscles. These muscles play assisting roles in various shoulder movements such as rotation and lifting. The muscles that make up the rotator cuff all have fibers that blend into part of the shoulder joint and as such work together to provide stability and help protect against injury during functional movements, lifting, sports and work based activity. If one muscular component of the rotator cuff has a specific pathology such as a tear or tendinopathy, the others can still provide the necessary assistance to the shoulder joint to maintain stability. 

Rotator cuff tears are always painful:

This is not always the case! Studies have shown that across large populations, many people demonstrate rotator cuff tears even without having any shoulder symptoms. This may be attributed to the fact that many individuals experience ‘degenerative’ tears of the rotator cuff group. This is seen during the aging process, and as such may not be resultant from a traumatic incident. The body is excellent at adapting to ensure pathological structures of musculoskeletal origin are not placed under excessive or potentially harmful forces. This is a positive thing to be aware of when recovering from a rotator cuff tear, as there is evidence showing that people can experience good functional movements, and minimal to no pain even with tears. 

If I have torn my rotator cuff, I will need surgery: 

Again not always the case. Although there is evidence to suggest that outcomes may be better for certain types of rotator cuff tears (smaller full thickness tears), there are individual factors, and other underlying considerations to take into account that may lead to an equally effective treatment path if managed conservatively. Exercise & rehab can be an excellent alternative.

If you have a rotator cuff tear, it is important to discuss the options of treatment with your treating health practitioner, to determine which treatment pathway is most appropriate for your case.