@Cyn hey! I have fibromyalgia and was on tamoxifen for 4yrs but had a recurrence. I had no side effects though. Im now on Aromasin post chemo 2 years on after switching from Arimidex. I suffer cramping all over my body but its not the meds its from chemo as it shrinks the sheath over the muscles. I do have lower back and hip pain. All of it doesnt help the fibro. I take magnesium in water too plus caltrate and vit C. It helps. I also take panadol osteo on a bad day and it really helps. The other thing that has helped me is my exercise physiologist and stretching so important. X Melinda