It looks like you have a Starter account based on your post tag, so it's worth noting that the social tool is accessible on with a Marketing Professional subscription or above. I'm wondering if you're looking in a different place if you don't have access to the social tool?
I wasn't sure what level of tool I have because I have an account under a client. Is this information under my Profile? Either way, I am using the HS social tool for scheduling so I must have Marketing Professional.
I'll drop the error message I receive in the comments of this record. Thank you.