The goal of this observational study is to understand the approach to pain management before, during, and after surgery at Mulago National Referral Hospital. It is focussed on adult patients undergoing major surgery. The main questions it aims to answer are: * How often are combinations of pain medications utilised before, during and after surgery? * Do combinations of pain medications result in better pain control after surgery compared to single pain medications? Information on pain medications will be obtained from patient records. Patients will be asked to rate their pain after surgery every 6 hours for 24 hours.