Show sale prices on shopify product pages with strikethrough

I have a swimwear company and use shopify with some of my products in the sale. On the sale collection page the original prices are showing with a strikethrough and then the sale price in red which is correct. However when I click on an item and I am on the product page directly it only shows the new price. It doesn't show the old price anymore with the strikethrough. See attached screenshots for examples. The sale collection page is fine but I need the original prices with the strikethrough to show on all the product pages also, I don't know why it's not showing