Ok so your shoulder has been hurting for a while and your Physio has diagnosed you with a Rotator Cuff injury. What the hell is a rotator cuff? How do I get rid of this pain!?
Firstly, the rotator cuff is a group of four muscles which help to stabilise the shoulder. The shoulder is a ball and socket joint, similar to the hip, however the shoulder has a shallow socket in comparison. What the shoulder lacks in stability it makes up for in mobility, generally speaking, a healthy shoulder has almost 360 degrees of movement so it needs help from the surrounding muscles to maintain stability through movement. There is also another structure inside the shoulder joint called the labrum, which helps to deepen the joint and provide stability.

How does my Rotator Cuff get injured?
Rotator cuff injuries usually occur either acutely (immediate sharp pain) or over time (gradual increasing dull ache). Acute rotator cuff injuries can often involve a tearing of the rotator cuff tendons and leads to pain and weakness of the shoulder. Gradual onset of shoulder pain can be associated with repetitive overhead movements, which can lead to smaller tears in the tendon and inflammation around this area.
One of the main factors which can influence shoulder pain is the position of the shoulder. The further forward the humeral head (the ball) sits in the socket, the more compression of the tendon occurs and leads to injury.
 
How can I fix it?
Having your shoulder properly assessed by a qualified Physiotherapist is the first step in diagnosing a Rotator Cuff injury. Investigations such as Ultrasound or MRI may be relevant if the Physiotherapist feels there is significant injury. For acute rotator cuff tears, a small period of immobilisation in a sling or in some cases, just with some tape, will help settle the pain. Once pain and inflammation are under control then you need to get the shoulder moving and gradually strengthen the rotator cuff tendons and surrounding muscles.
For the gradual onset type shoulder pain there is usually a biomechanical cause for the loading of the tendons. Thorough assessment by a qualified Physiotherapist is a must to get to the bottom of your shoulder pain. Initially settling down the pain and inflammation around the tendons and encouraging gentle pain free movement is the first step. Then gradually increasing the load in the shoulder until the strength is back to normal

How can I prevent this from happening in the future?
Continuation of the strength and flexibility exercises prescribed by your Physiotherapist will help decrease the likelihood of re-occurrence. Identifying aggravating positions i.e. overhead movements or reaching in awkward positions will also decrease the likelihood of re-injury. If your job is a relatively sedentary and requires hours of sitting at a time, trying to break up your day with standing/walking will help, also an ergonomic assessment to ensure your workspace is properly set up to suit you will help ease the stress on your shoulders/neck.