Knee replacement - did anyone have severe back pain after surgery?

Yes, I had my Surgery May 3rd! Rt knee replacement and my lower back pain is very bad! I use heat and Advil. Hot showers. But as well, I've experienced nausea, no appetite and no energy.
But that's just me..

It is not an uncommon side effect of total knee replacement - you can develop sciatica pain as a result of nerve irritation in the lower back, or from pressure on the piriformis muscle in the back of the upper pelvis. This will cause pain to radiate down into the hip and possibly into the leg. It is also possible to have impingement of the pudendal nerve in the same area. This can cause pain and numbness into the genital area. If this pain is bad enough and does not resolve quickly, seeing a pain management doc for injection therapy might be helpful. Also, nerve pain may respond to certain medications other than opioids -meds like gabapentin and pregabalin.

I have some upper hip near lower back lain but my P.T says its my leg muscles working during therapy and stretching when leg is straightening. Its just a little annoying but i find that heat on that back hip is wonderful! Dont worry. I had my surg aug4 th 2011.