I had low back surgery last week. There were no complications, but now my calf muscle is red and very sore. Is it related to my surgery?

Yes. Call your doctor right away. Your symptoms sound like a blood clot in your calf. This condition is called deep venous thrombosis (DVT). DVT can happen after many kinds of surgery.

In DVT, blood clots form in the veins of the legs. If the clot breaks free, it can get stuck in the little blood vessels in your lungs and cause a pulmonary embolism. A pulmonary embolism happens when the blood supply is cut off and part of the lung collapses. This problem can cause death.