sidebar and blog posts missing how to correct?

Hi there… https://www.mscott-photography.com I have a left sidebar showing on all pages which I want it to except for the blog page! I di not design this theme but cannot get an answer from the designer who has gone another way since this project! What am I missing?? ALSO in trying to figure it out NOW all of a sudden my blog page loads BUT when I click on a post it shows an internal error so I must have gummed something up!!! I REALLY need my blog posts to be loading soon so PLEASE any help is appreciated on where to look and what the code should read heavy sigh…