ache, be in pain, painful
痌 centers on physical suffering: aching, being in pain, or feeling painful. It describes a state of bodily discomfort.
痌 combines 疒 (sickness) with 同, which likely contributes a phonetic element. The exact historical development is uncertain, but the structure suggests a phono-semantic compound related to illness or pain.
The sickness enclosure 疒 wraps around 同, like a painful illness spreading through the body. Imagine the same ache repeating everywhere.
For トウ, picture a toe throbbing with pain: toe -> トウ, and the ache is inside the sickness enclosure.