I'm trying to remember the title of a fantasy novel I read years ago. I remember reading it in paperback format in the early to mid 90's, so I'm guessing it was written in the 80's or 90's. The protagonist was a female. I believe she had red hair and lived in a castle. I know the climactic scene involved her climbing a tower and facing various magical obstacles before facing off with some kind of wizard type character. I also want to say that fire played some integral part, but I can't remember for sure. Anyone know this book?
Did she kill dragons before facing off with the wizard? If so, could it be The Hero and the Crown, by Robin McKinley? It was published in 1984 and features a red-haired heroine who develops a protection against fire that allows her to kill dragons. Near the end of the book she climbs a magical tower to fight a wizard. There's a summary of the story here.
This makes me think of the Darkover series by Marion Zimmer Bradley. I just Googled it and one of the novels in the series is called 'Stormqueen!: A Darkover Novel'. The cover has a redhead atop a tower with lightning all around. There was lots of magic in that series, strong female characters, issues about using magical powers, hiding magical powers, escaping from towers, etc. I read the series in the 80's.
Could it be "Bronwyn’s Bane" by Elizabeth Ann Scarborough? It was published in 1984. The cover shows a red-headed female warrior fighting some kind of serpent with a castle in the background. I did read it, but it was many years ago and I don't remember all the details.