Everywhere that sensory nerve has its branches end, and sometimes over every sensory quality it transmits. So the feelings can switch between different sorts of pain, or temperature, or vibration, or pressure. It depends on what kind of damage occurred where along the nerve.

I've learned it's on mesopotamian clay tablets, with a description of symptoms and treatments - although it was handled by priests, since they thought it was caused by demonic possession or curses (by either a god or a human). Does trying to find out which cause "applied" in each case as early psychotherapy?

The eighth and ninth clay tablets of the Gilgamesh epos describe his grief and wanderings after Enkidu's death, with an account we would read as depression today.

Later on Herodot and Plutarch describe it as a disease in their medical texts, but they called it melancholia.

Involuntarily training stops in 70+ due to fractures and longer healing periods, dizziness, fall risks, joint pain etc are common.