If the cause of present suffering were located exclusively in the past, the most that could be done would be to endure the suffering while not creating any new kamma leading to future suffering. The Buddha heaps ridicule on this idea.
"If the cause of present suffering were located exclusively in the past, no one could do anything in the present moment to stop that suffering; the most that could be done would be to endure the suffering while not creating any new kamma leading to future suffering. Although this was the Jain approach to practice, many people at present believe that it is the Buddhist approach as well. Meditation, according to this understanding, is the process of purifying the mind of old kamma by training it to look on with non-reactive equanimity as pain arises. The pain is the result of old kamma, the equanimity adds no new kamma, and thus over time all old kamma can be burned away. In this sutta, however, the Buddha heaps ridicule on this idea...." ~ Thanissaro Bhikkhu, translator's introduction Devadaha Sutta (Majjhima Nikaya 101)