Finding the malicious software in my stores .com address.

I keep getting a message from Facebook when I try to attach to my Shopify address, that they are detecting malicious software, and they won't connect to my site, or let customers be directed there with the Sales button. I have attached the message from them, and the one I got on Shopify, when I tried to connect to Facebook. It was all working fine, until I had another Freelancer Tech, go through to set my pricing up at a 35% mark-up from cost, and to set up my .com address.