Why does my arms n legs feel stiff sumtimes?

Arm/leg stiffness : By arm and legs do you mean hands, feet, joints, fingers? If this is been an ongoing problem, it may be due to a systemic condition. Examples include rheumatoid arthritis and a few others. Mention this to your doctor so you can get examined, obtain labs and possibly imaging studies. Its important to get a diagnosis earlier than later. Good luck.