No, it is not a sin as if one is not sexually active, there can be no contraceptive action. The principle of the double effect may apply as well.
However, you would be wise to review the package insert for birth control pills. There, you will see that the BCP is not indicated for the treatment of any of the conditions you mention. This is called an off label use, and while legal, it is an unproved use in the eyes of the FDA.
If faced with such a medical condition, I would consult with the *Pope Paul VI Institute. *They have a great track record in finding the source of the problem in a manner that is morally upright and treating it in a manner that aviods sin.
Sometimes BCPs cover symptoms rather than getting to the root of the problem or treating the problem.