Is my breast naturally asymmetrical or is it caused by implants? (Photo)

From the submitted photos it does appear you had asymmetry prior to your surgery. If not addressed during your augmentation it will still be present afterwards. Sometimes it becomes more obvious after surgery since the breast volume is increased and they are scrutinized more closely by you. A revision would bring them into better symmetry.

Before implants, your nipples were symmetrical but one breast was slightly larger. It does appear that one implant has not completely dropped. You could try oral Accolate and external ultrasound treatments to see if the pocket can be softened. Otherwise, it will take surgery to reposition the implant.