Adam suffers in many different ways throughout I Am the Cheese. Although he undergoes physical pain, in the form of headaches, nausea, and even a major head injury, it's the emotional suffering that sticks out to us. After all, emotional suffering is usually more enduring, and it doesn't go away quite as easily. Adam's constant anxiety, coupled with the discovery of his traumatic past and the eventual loss of his parents, leads to a kind of everyday suffering that most of us are lucky enough never to experience.
Adam's bike ride is a conscious attempt to escape the suffering of his real life.
Adam's suffering makes him stronger.