When we talk about the value of a workers comp case in Illinois, we look at three different things - how much money you made in an average week before the injury, the part of the body that was hurt, and the nature and extent of the injury. This means how bad the injury was, whether you still have symptoms, whether it affects your ability to do your job, whether you had surgery, etc.
Most parts of the body are assigned a number of weeks. For example, if you had a hand amputated, you would be entitled to 60% of your average weekly wage for 205 weeks. Interestingly enough, even though the shoulder is part of the arm, shoulder injuries are considered part of the "Body as a Whole". This means that they are based on a percentage of 500 weeks. Of course, 500 weeks is the equivalent of having lost your entire body just like 205 weeks is what you get for losing your whole hand, so don't expect to get anywhere near 500 weeks of pay.
In general, the value in Illinois workers comp of cases with shoulder injuries varies with the type and severity of the injury. Even something common like a rotator cuff tear can mean several different things (biceps tendon tear, supraspinatus tear, infraspinatus tear, labrum tear, SLAP tear, etc - maybe a combination of the above). If you hurt your shoulder, go to a good surgeon and work hard in physical therapy. I've seen very widely varying degrees of healing after these injuries. I've seen people who have multiple surgeries and never get right, or people who develop frozen shoulder.
As a rule of thumb, full-thickness tears are worth more than partial-thickness tears. Multiple surgeries are worth more than one surgery. Cases with permanent pain and restrictions are worth more than those where someone heals up 100%. Of course, the exact value of any specific case is very fact-specific, so we can't tell you what your case is worth without speaking with you and reviewing your medical records and wage statements.