You will get more done and you will feel better doing it. Make sure your workstation is set up to reduce fatigue. Re-adjust your chair between each work task. Check your posture to make sure you are not slumping. Take an inventory of what feels tight or sore on a regular basis.
Chances are that a sore area needs to be stretched.
It does not take much time to release built up stress. Pull your shoulders down and gently lower your ear to your shoulder each way. Hold for a count of five. Repeat three times. Stretch your arms over your head and interlock your fingers with the palms turned up.