When using a computer it is good to practice regular health and safety exercises. It is common with using computers that people get Occupational Overuse Syndrome from repetitive use of the mouse and keyboard. Every hour of computer use you should take a 5 minute break and strech your neck, shoulder, wrist, hands, upper and lower back, legs and eyes. You also should get up and go for a short walk to keep from getting stiff.
The best way to strech your neck is to gently lower your ear to your shoulder and hold for 10 seconds then slowly roll your chin across your chest to the opposite side and hold there for 10 seconds.
Turn your head to the left and hold for 10 seconds then the same on the other side.
To loosen your shoulder roll them forwards and then backwards. Repeat a few times.
Interlace your fingers with palms facing outwards and raise your arms over your head and hold for 10 seconds. Also do this while standing and gently lean side to side in order to strech your back.