Switched from hormonals to chemo(docetaxe)

MymomisstageIV

My dear mom was switched from faslodex(after two years) to docetaxel(every three weeks). She had Pet scan which showed some uptake near joints and she was in a lot of pain. As onc said, it was hard to distinguish whether the uptake was in joints or bones. So I guess he could'nt say if it was new mets or not. Progression or not. Pain had developed over several months and was in knees, ankles and wrists. Is there anyone dealing with similar problems or has in the past? Onc said this chemo should reduce her pain..when could that happen? Sad to see her like this...