First you would have to be evaluated by a medical professional well versed in the coolsculpting procedure. Preferably someone that was trained at CoolSculpting University. This would determine if the area you are concerned with is appropriate for the coolsculpting procedure. If treatment is indicated, the main side effects are soreness, redness, bruising and numbness at the treatment area. The system is designed to only teat/effect the adipose (fat) tissue under the skin. The bones and organs will not be effected. The only way it could affect the breast tissue is if it was placed directly on the breasts. Ensuring no breast tissue is inserted into the applicator at time of placement is essential.
I highly recommend coolsculping over Kybella (off label). The newest coolsculpting heads (Cool Advantage) are able to treat areas that previously could not be treated due to there not being enough fat to reach the treatment area of the applicator. This issue has essentially been eliminated as the new applicator is almost entirely active treatment area. The procedures used to take an hour to perform and now are down to around 30 minutes. Plus it is totally non invasive. No injections. Kybella off label can be very dangerous. The compound was not intended for other areas and the fat is different in make up in different areas. I have seen horrifying photos of Kybella used off label on the inner thighs. It liquefied the fat as intended, but also necrosed the skin and left the patient with large open wounds that required surgical closure. The scaring on this patient will be quite noticeable on the inner thighs. I can not imagine if that were to transpire on the flanks.