Excerpt option i.e. read more not working properly

After I publish an article, and click the read more on the home page I get a 404 not found instead of seeing the entire post. Note my excerpt is set to 75 words and posts are a few hundred words so there is more to display then the excerpt. I also have a secondary issue that the image I place with post at top left or right of article, do not show in excerpt on home page. Note images are thumbnails so they should fit fine. Thanks for reading!