Herbal Pain Relievers in Cancer Treatment

My granddaughter (age 7) was diagnosed 12 days ago with ALL (Acute Lymphoblastic Leukemia).
As she undergoes her chemo & the multitude of drugs, she is in lots of pain. The morphine they gave her in the beginning causes cramping, and she no longer wants to take it.
My daughter & granddaughter are vegetarians, and they eat pretty healthily.
My daughter is looking for some natural herbs for her to soothe the pain. Please advise your thoughts.

Homeopathic arnica, strength 30x, is helpful for pain.
The herbs hops and valerian ease pain and calm the nerves to allow sleep. Because they have sedative actions, they may cause excess relaxation with any sedative drugs. Hops can be taken as a tea by steeping a teaspoon of the dried herb in a cup of boiling water for 15 minutes. The adult dosage is half a cup daily. For a 7 year old the dose would be one quarter of a cup daily. Valerian root should be taken as a tincture, because it has a strong taste that is not pleasant in tea form.