Deprecation means just that: deprecation. It does not mean that code is missing. It is still there and working. It's unlikely that this deprecation causes the issue you are seeing.
For me it rather seems that you own custom code imports the Java package "org.apache.sling.jcr.resource", which has been removed. But there are replacements available so your custom code can be adjusted easily.
but in other this would mean, that these cq-social modules in question are not runnable on AEM 6.4, and this would affect a non-upgraded version as well.
Just reviewing my AEM 6.4 SP3, I found no cq-social-storage module, cq-social-commons has the version number 1.9.76 and cq-social-blog is also gone. I guess that you should verify the upgrade logs if anything has gone wrong. Does your application run on an vanilla (non-upgraded AEM 6.4) version?