It will come! I'm 8 days out of surgery. It took 3 days after surgery before I had my first BM. I felt the urge to go and tried sitting on the toliet for 5 mins but nothing came. It hurt so bad to sit so I got up walked around all day until the urge so was extreme. It still took a good 3 to mins after i sat down for it to come but it came. I also took oxys every 6 hours to stay ahead of the pain. I took stool softeners twice a day. Yes, the oxys can constipate you but I believe the delay was because of the anesthesia. It slows down your gi system. It takes a bit for it to be back to normal. I wouldn't worry too much that you haven't had a BM yet as your only 3 days out. Also, be careful on how many laxatives you take as it will cause diarrhea and you don't want that.