Below are the main rubriks (i.e strongest indications or symptoms) of Acid Phos in traditional homeopathic usage, not approved by the FDA.
BACK AND NECK
Back and neck
Formication in the back.
Gnawing on the scapulae.
Heaviness in lumbar region, increases to pain in the legs. θ Tabes dorsalis.
Burning pain in a spot about small of back.
Burning in lower half of body, from small of back to pit of stomach downward; extremities are cold to touch.≡ more ...