One month ago, my right leg started to pain me, it is a daily pain nonstop-from knee down and feet too.it is swollen too as my face. i feel pain when walking too. today, a place behind knee is paining me strongly,knee and feet less. thank you?

Any history of leg or knee trauma? The differential diagnosis here would include phlebitis, knee pathology or a Baker's cyst behind the knee. I would start with an examination by your physician or an orthopedic specialist. Appropriate studies will be ordered which may.very well include an ultrasound of the leg and/or an MRI of the knee depending upon physical findings.

Joint Pain, swelling, facial swelling, and difficulty walking sound like a multi system problem, possibly a Rheumatological condition which requires a full examination and laboratory testing. Please see a physician to begin the workup. If you have fever or chest pains with these problems go for immediate help.