I'm Miles from the Social Care team at Shopify. I'll be happy to work out what might be going on. If my suggestions below don't help, please reply with your URL and some screenshots of what you're seeing on desktop so I can take a better look for you.
Firstly, have you added any apps relating to products at all? If so, some apps can affect coding in a store. Have a look at your theme's coding (Online Store > Themes > Actions > Edit Code) and see if any of them have been edited. Next to each coding file, there will be a purple dot if there's been a recent edit. Click on the theme file to see if you can find the cause of the problem. Some of the theme codes I'd suggest looking at would be theme.scss.liquid, product.liquid and theme.liquid. If you're not too comfortable with coding and you're using a Shopify theme our theme support may be able to help you. If that's the case, please reply again to this thread letting me know, and I'll get the ball rolling with that.
Another possible issue could be the browser you're using. Check out this guide for a list of recommended browsers. If your browser is on this list, I would recommend clearing your cache and taking another look to see if that resolves the issue. It's also a great idea to keep your browser updated to the latest settings as well as the computer or laptop you're using.
Once you've worked out the issue, it's always a great idea to look at your store's design and work out how you can convert your traffic into sales. Have you heard about Shopify Compass? Shopify Compass provides you with free webinars and courses on things like store design, marketing and more. This is a free service for everyone, and we add new content every week - including live webinars. I'd highly recommend checking this out to help your store make some sales.
As I mentioned above, if you need any further help at all, please reply to this thread. Thanks!