Y not,
An arahant does feel pain as a burden because he/she does not experience it as me and mine anymore. Therefor the pain does not become a burden. Yes, in a sense an arahant is dissociated from the pain when there is no more I and mine-making of the pain. Meditation masters tell this from their own experience. One can experience intense pains without any re-action in mind. One can be totally unshaken with intense pains.
In a certain sense this is a kind of dissociation from the pain, but not in a sense one does not feel the pain. One is dissociated from the pain because everything that causes association with the pain, i.e. avijja, tanha, ditthi and mana, do not arise anymore.
One of the most important ways of assocation with whatever we experience is sakkaya ditthi . These must end first.
If, like an arahant, there is no association anymore with whatever is experienced, then at that moment, it becomes perfectly clear that mind, as that which experiences, and object of mind, as that what is being experienced, do not really mix.
The causes for mixing up mind and mind-objects are gone.
Siebe