I had knee replacement sept was doing great and now have more pain even at nite. dr released me a month ago and is hurting more?

Several possiblities: If you are having increased knee pain, you need a clinical re-assessment. If the knee is swollen and warm, then it is inflamed which raises the possibility of an infection. In that case the fluid should be drawn out and send for culture and several other tests to see what is going on. Other possibilities are referred pain from the hip and the back. An examination should be able to help here.