I have a kidney stone and a urethral stent in. For a week I have headaches, nausea, hot flushes, pain when weeing, back pain, sleep a lot n not hungry?

Here are some ... If what you described occurred after the procedure of stent insertion, what you are feeling now might be related with anesthesia, pain medication, etc. With these in mind, ask and talk with Doc timely so to deduce possible causes for proposing reasonable Rx/care timely. Best wish ...