What Causes Tightness In Legs?

for the past 2 months I have been experiencing tightness in my legs, I notice when I put my shoes on they start feeling tight and pressure and when I go to bed at night I really notice it. It feels worse than restless leg syndrome. I sit at an industrial sewing machine all day and I am getting worried that it may be a blood clot or hopefully you can give me a better idea of what might be going on.