The soldier boy in the poem is described as a young man full of vim and zest.he does not want to accept his grave injury and his defeat and thus he repeats to the poet that his injury was just a small pain even though it was a grieve one.he also thinks about his wife and mother as well as the society and thinks that he has not been able to fulfill their expectations .In this poem the narrator meets a dying soldier who inspite of grave injuries has a smile to hide his deep wound. The soldier had fought the battle restlessly and shared his experiences with the narrator. The agony of  the soldier has traumatized the narrator who later dies of with a small pain in his chest. This poem is a anti-war poem which teaches us the side effects of war & the results it has shown in the lives of people. Hence, advising us to understand the real agony of people involved in war which had never given happiness to people or the nations fighting it.
if helped plzz mark as the brainlist plzz.. ^_^