The information provided here is not a replacement for a doctor. You shouldn't use it for the purpose of self-diagnosing or self-medicating but rather so you can have a more informed discussion with a professional TCM practitioner.
Because it is a herb specifically indicated to treat sore and aching limbs as can be seen on Fleeceflower Stem's page.
Fleeceflower Stems is a Neutral herb that tastes Bitter and Sweet. It targets the Heart and the Liver.
Its main actions are: Nourishes the Heart Blood and calms the spirit. Tonifies Blood, improves circulation and dispels Wind. Applied externally, it relieves itches and rashes.
Palpitations Insomnia Restlessness Itchy rashes Rheumatic athralgia