I've got some quests that I have no intention of doing like the Underdark/forge? one for the Companions that I presume turns you into a werewolf. I also recovered a flute that I discovered boosts all your magic skills a point which isn't good for me given that I'm a warrior. Am I doomed to have these quests in my log for all eternity or is there a way to abandon them?

IS the flute named?

If it is i believe you turn that in to one of the members of the bard's College in Solitude for some skill increases.

Your OP contains spoilers, just noting

Also, I do not think you can get rid of quests, just ignore them. You can however unmark them so the quest arrow does not show, so the quest looks to be "inactive".

you're doomed