What Causes Pain And Swollen Veins On The Knee Caps?

the viens on my knee caps are swollen, red, and hold heat. It is severly painfull to get up from a seated postion as well as sit down from a standing position.I have just 2 months ago) found out I have lung cancer type 2B lower left lobe that is inoperatable. could this be a symstom.

I am 56 years young, fair health, only 1 surgery in 1985 ahystorectamy and appendecamy.