Right shoulder burns after an hour of mouse work, left side is fine Desk Setup

Reach and abduction. Look at where the mouse actually sits: if it is to the right of a full width keyboard, your arm is held out at an angle and the shoulder holds it there statically all day. That static hold is exactly what burns between the blade and the spine. Three things that worked for me, cheapest first: get a keyboard without a number pad so the mouse comes 10 to 12cm closer, set the height so your forearm is level rather than reaching up, and rest the forearm on the armrest or the desk instead of floating it. The keyboard change alone stopped the burning within a week for me.

Check whether you are gripping. Heavy CAD work makes people claw the mouse and the tension runs up the forearm into the shoulder. Deliberately let the hand go slack for a few minutes and see whether the burn changes — if it does, the mouse is probably too small for your hand or too heavy in its glide.

Worth swapping the mouse to the left hand for an hour a day while things settle. Clumsy for a week, and it gives the right side a real break. If it is still burning after a few weeks of setup changes, get a physio to look at it rather than buying more equipment.

Shortcuts, genuinely. Every action you move from the mouse to the keyboard is load you are not putting through that shoulder. I learned about fifteen of them and my mouse time dropped by roughly a third.