Is suffering caused by oneself, others, by both, or spontaneous? According to popular belief of Karma, suffering is caused by oneself. I would like to know: 


Is one's own suffering caused by oneself? 
Is one's own suffering caused by others? 
Is one's own suffering caused by both oneself and others? 
Is one's own suffering spontaneous?
The teaching of 'good &amp; bad kamma' is not Buddhist but is merely a conventional &amp; universal understanding about 'personal' behavior found in most cultures &amp; religions that is also part of Buddhism. The doctrine of kamma in Buddhism is called 'lokiya dhamma', which means a 'mundane' or 'worldly' understanding based on the view of 'self' or 'persons'. 

To the contrary, the suttas state (eg. MN 56) that the unique or special teaching of the Buddhas is the Four Noble Truths, which includes the Noble Eightfold Path that ends kamma (refer to AN 6.63). The Noble Eightfold Path ends kamma because its fruition renders all kamma as 'not-self' ('anatta'). Such understanding in Buddhism is called 'lokuttara dhamma', meaning 'transcendent', 'supramundane' or 'beyond the world'. 

Thus, according to 'lokuttara dhamma', suffering is impersonally caused by the element of ignorance according to the process of Dependent Origination. 

In short, the Acela Sutta answers the question exactly. 

Note: the Acela Sutta states the view that suffering is 'self-caused' is a form of 'Eternalism' and the view that suffering is 'other-caused' is a form of 'Annihilationism'.