I've been on Anastrozole (Arimidex) for 3 mos, the first pain was in my knees but it wasn't significant or there all the time - I'd never had knee pain before. In the past 2 mos my hip and back pain (aching and stiffness) is pretty significant. Saw my oncology nutritionist a few days ago who added calcium, vit D and Glucosamine/Chrondroitin to my daily Alive Women 50+ Vitamin. She looked at all the dosage amounts, some I take in the AM others in PM. Will try this for a month and if symptoms don't subside might try a different AI. I also get a lot of calf cramps at night that can keep me from sleeping. I do Pilates 3x a week which helps on so many levels. I'm 53 so I wasn't used to aches and pains until diagnosis 14 mos ago. Diagnosed IDC, PR & ER +, HER2-, nothing in lymph nodes, stage 1. Did lumpectomy, radiation and full hysterectomy (minus the ovaries), no chemo luckily.