It sounds like you don't have your domain routed to your Shopify server.
I would start there (Shopify admin > Online Store > Domains)
Founder of Speed Boostr (Shopify optimization and dev agency). Creator of Theme Scientist (A/B testing app). Creator of Order Automator (app that auto tags + fulfills orders, send emails). Creator of Tip Jar (add a tip button to your store). Creator of Shopify Analyzer (free performance analysis tool). My team also builds custom apps and automated solutions. Enjoy the adventure!