Do you mean a long post page with lots of information, or just any web page you visit on your WordPress site? Do you have a lot of plugins? Ads? Large graphics? Links to graphics off-site? Lots of links to off-site websites? All of these things and others can slow down the loading, even to timing out, of a page. Look at EVERYTHING you have included on a page. Something might be pulling in huge files or a plugin or pulling a load on your database.
Now, I’ve looked at your site and I’ve found a LOT of errors and they are related to about the same thing.
<A href="https://papercandies.com/information.php?osCsid=b23a25613b360b143689b733a68cda03&info_id=33" target="_self">Meet the Artist</A>
1. Do not use capital letters in any tag. It isn’t good XHTML.
2. The link you are using is very odd, and I think it is generated because you don’t have the link right in the first place.
Are these “categories”? More likely Pages. The correct link for Pages is:
<a href="https://papercandies.com/index.php?page_id=33">Meet the Artist</a>
I recommend that you use the wp_link_pages() instead of using an exact link, if you can.
If you have set up your permalinks and the .htaccess file to use different redirects, you’ll have to customize these links as you see fit, but they are generating php errors.
Here is a link to your page’s validation report: https://validator.w3.org/check?verbose=1&uri=http%3A//papercandies.com/blog/%3Fp%3D6