If you have upper back pain or any pain in any areas of your back a good way to get rid of back pain including upper back pain is to apply some heat to the pain.
A good way to apply heat is to rest a heating pad behind your back to allow the heat from the heating pad to reach your upper back.
Applying Ice after the heat can also help reduce swelling and pain and taking over the counter pain relievers that contain NSAIDS.
Or you can use either just the ICE or the Heating Pad to keep the pain away and work on your posture when sitting as that can cause back strain and back pain.
A heating pad helps to relax and sooth the muscles and tissues.