"Metamorphosis"

I noticed a pattern in Kafka's work. Professor Talbird mentioned about a significant repeat of injuries to the side of the characters in Kafka's stories. In "The Country Doctor", the patient had a large wound (page 79) on the right side, near the hip that was opened up. In "Metamorphosis", the similar wound is stated. In the scene, Gregor was trying to squeeze through the doorway and "one side of his body lifted itself up" and it was "completely abraded" and it left "ugly stains on the white door" (page 24). This poses the question of why is there a constant motif of this wound on the side? Also, I still am curious as to why the cleaning woman was never afraid of Gregor. She treated Gregor as if he was normal, even trying to have conversations with him. Was this woman of any foreshadow in Kafka's life as well?