Hello and Welcome to 'Ask A Doctor' service. I have reviewed your query and here is my advice.
Considering the fact that you had this
shoulder pain two years ago, that you have it during your work sitting at the table, and it gets worse as the day goes on. In my opinion your complaints might be related to a cervical pinched
nerve due to a disk herniation, or it might be related to
rotator cuff problem on the shoulder joint.
These problems both are commonly accompained by shoulder pain that radiates to the arm or hand, and it gets worse by bad posture.
To put the right diagnosis you should consult a doctor for a physical examination, and MRI is the best examination to diagnose this problems.
For pain relief you can try taking
Naproxen , (antiinflammatory drug) daily.
Exercises and
physical therapy also help and try to keep a good posture during your work.
Hope I have answered your query. Let me know if I can assist you further.