How can I say this politely; this sounds like bullshit to me. I think this psychic has lied to you. One of the most recurring mistakes unaware people do is to make that separatist comparison of body and soul, and as HP Zevios Metathronos has stated once, this separatist thought has been created by Christianity.
You are your soul. You are both a soul and a body of course, but you have always been a soul even before you started existing as a body in this lifetime, too. And what's in your soul will usually manifest in your physical body just like it is, such as an anomaly or something. So if there was actually a part of your soul missing, I think this would be seen in your body too.
It sounds to me like this psychic would even complete what they told you with the usual new-age "soulmate" belief, stating that your soul will only become complete when you find your own "soulmate", because without it, "you are only half". "Half of an orange". That your "soulmate" is your "missing half". Which is bullshit, too. We create intimate connections with whomever we decide to, and although a love partner can make our lives happier, we're still one and a whole without them, and we're actually supposed to feel complete with ourselves first, before pursuing a love relationship with anyone. I could write more on my thoughts about that here, but then this would go off-topic.
