Constipation Relief :(

Any ideas for constipation relief you guys have would be greatly appreciated! I had a minor surgery on Tues Dec 15 & was prescribed Percosets for pain relief. They told me to take fiber while I was using them because apparently they are notorious for causing extreme constipation. Well I did take fiber, also ate fiber rich foods & drank lots of water. But I haven't had a bowel movement since Mon Dec 14, and I'm in a lot of pain now from constipation & need advice!! Please help :(