For pre-residency candidates who are applying in more than one specialty, I recommend being up front with your letter of recommendation writers. A few clients have asked me if they should ask recommenders to compose letters for different specialties or one letter that's more generic. The former is your better bet. First, your letter writers will be appreciative if you are honest with them. Second, you'll get more appropriate, and thus stronger, letters.
Applying to more than one field - especially if one of them is competitive - is not that uncommon. There's no reason to be embarrassed.
Contact me for help with your application. 'Tis the season.