I was using 50 mg Clomid and 12.5 mg aromasin ED for PCT, right around the two week point my knees, hips, shoulders really started to ache. I stopped the aromasin and within 36 hours the pain went away. I'm not saying it was the aromasin, it was the combo that knocked estrogen too low.
I've heard, and plan on trying the 12.5 mg aromasin as a bridge between cycles.