This might be referred from the back or hip joint, it may be circulation related or it may be due to past trauma.
Cause: Chair back not supportive causing disc pressure on nerves that go down the leg.
Solution: Adjust lumbar support of chair so the lower back does not slump backwards. See section on chair adjustment.
Cause: Seat pan too deep.
Solution: Replace chair so seat cushion does not cut off circulation behind knees – you should be able to place 4 fingers from the edge of the seat to the back of your knee.
Cause: No footrest
Solution: The chair height is determined by the desk height so a shorter person working at a fixed desk should have the chair raised. If this puts pressure on the thighs i.e. you can’t slide your hand easily between thigh and seat, you need to use a footrest to help relieve this pressure (see image).
Cause: Working with legs tucked under chair.
Solution: Never sit with legs tucked beneath you OR with your knees crossed - use a footrest to stretch out your feet and open your knees. Move your ankles around regularly.
Cause: Sitting still for long periods
Solution: Stand and move every 20 minutes. A sit-to-stand desk works well if you are wanting to continue with computer work. Otherwise make a habit of taking regular breaks from the sitting position to eliminate leg pain.
It is advisable to consult your Doctor if symptoms do not change in a 48 hour period and after you have attempted to make work place changes.