References – SN 36.21: Sivaka 
“In this passage where the Buddha lists illnesses and calamaties (AN 10.60), he separates kamma out as a cause of those things. However the cause of being subject to these things is because of making good or bad kamma. Is kamma [in this list] a direct, proximate cause?” Answered by Ajahn Karuṇadhammo. [Kamma] [Sickness] [Conditionality]
Sutta: SN 36.21 Sīvaka: The Buddha refutes the notion that kamma causes everything.
The Four Foundations of Mindfulness [2015], Session 5, Excerpt 2
Readings by Ajahn Karuṇadhammo: [Feeling]
Reading: SN 36.7: Gelañña Sutta, “The Sick Ward.”
Reading: SN 36.21: “Sivaka.”
Reading: “The End of Rebirth,” The Stillness of Being by Ajahn Viradhammo, p. 67-77.