It is extremely unlikely that an otoplasty procedure will negatively affect your hearing. Ear pinning will not improve your hearing either.
The ear is made up of three parts: the outer ear (the pinna), the middle ear and the inner ear. All three parts contribute to hearing, but this is mainly down to the middle and inner ear. As otoplasty surgery only concerns the outer ear, it is very unlikely that surgery to this area will affect your hearing.