Throughout the course of the play, Hamm asks five times, “Is it not time for my pain-killer?” The first four times he asks, his servant Clov tells him, with increasing anger, that no, it is not time for his pain-killer. The fifth time he asks, Clov tells him that it is time, but that there are no more pain-killers and that he will “never get anymore.”
In response, Hamm asks, at first pitifully and then again “In a scream,” “What’ll I do?” His response indicates that he will be unable to carry on without his pain-killers. They make life bearable for him. The prospect of living or trying to live without them makes him feel desperate, lost, and hopeless.
Hamm is elderly, blind, misanthropic, and miserable. He suffers physical pain, but he also endures a sort of existential pain. In other words, the endless and insufferable meaninglessness of his existence causes him great and inescapable anguish. Indeed, he is, in his own words, no more than “a speck in the void,” surrounded by “Infinite emptiness.” By having Hamm repeatedly ask for his pain-killer, Beckett is emphasizing the extent and degree of the pain that he suffers, both physical and existential.
Hamm is also of the opinion that the pain he suffers is worse than any pain anybody else could possibly suffer. Arguably, therefore, the repetition of his request for his pain-killer serves not only to emphasize the intense pain and suffering that Hamm must endure but also to highlight how desperate and self-pitying he has become.