Yes, Detox from pain pills and other opiates is horrible. My boyfriend has been through detox a lot of times when he's been in and out of rehabs. It takes him weeks sometimes before he is really feeling well again. He says his whole body hurts.
I found out recently that instead of him going to rehab in Charlotte like he was supposed to. He was really at his parents house in his room detoxing himself. He called me 2 weeks later telling me he never went to rehab that he stayed there and had just in the last few days felt well enough to call me.