In the first lines of "The Raven," the speaker says that he is tired and reading an ancient book:
Once upon a midnight dreary, while I pondered, weak and weary,
Over many a quaint and curious volume of forgotten lore, (1-2).
In lines 10-12, the speaker says, "From my books surcease of sorrow-sorrow for the lost Lenore- / For the rare and radiant maiden whom the angels name Lenore- / Nameless here forever more." The speaker is trying to read to take his mind off his sadness. "Surcease" means a cessation or relief. He tries to read his books to get relief from his sorrow. His is distraught because his lover, Lenore, is dead. Lenore is with the angels now. The angels name Lenore - this is another way of saying they speak to her. Lenore is nameless "here" (on Earth) because she will never be there again in physical form to hear the speaker say her name.
The speaker is seeking relief from his grief. The raven is a symbol of death and a reminder of the speaker's grief over his lost Lenore. The speaker spends the rest of the poem trying to escape from that grief, from the literal and figurative shadow of the raven.
He was reading old books because his lover, Lenore, is dead. He was seeking relief from his pain. When he asks if there was balm in Gilead, he was asking if he will ever heal from her loss.