If it is the quality of your consciousness at this moment that determines the future, then what is it that determines the quality of your consciousness? Your degree of presence. So the only place where true change can occur and where the past can be dissolved is the Now.
Actually, the ability to choose presence depends on the degree of presence that's emerging in you. Ultimately, you are not choosing, there's nobody there to choose. When you think you are choosing, presence is simply emerging in that moment.
The intensity of the pain depends on the degree of resistance to the present moment.
Many people see themselves as a problem that needs to be solved. They also habitually see the present moment as an obstacle that they need to overcome or get away from. With awareness, an inner sense of spaciousness arises that enables you to look at your own mind, which is to say the human mind, with a certain degree of detachment.