Hi I Am Vasanth. I Have A Construction Tools Business

hi i am vasanth. I have a construction tools business a retail outlet. carpenter tools and materials. masonary tools and materials. I have a problem with my legs which i am unable to stand for long time (30 minutes). I have a feeling of aching back of my knee joint. I feel my something stretched at the back of my knee when i strech my knee completely. what could this problem be.