Where the shape comes from
The bed 爿 stood on end with a person 人 leaning against it, and two dots for the sweat of fever. It is never written alone, and everything it shelters is an ailment or its treatment: 病 illness, 疼 and 痛 pain, 疲 exhaustion, 瘦 thin. Note the outline — it is the shelter 广 with two extra dots on the left stroke.