Bootstrap shortcodes not working

I’m new to web development. Trying to get a site finished for a friend and I’m using bootstrap shortcodes as a quick fix solution.

The site is local so I’ll send a pic of what’s happening. When I shrink the window size, the elements don’t collapse and stack like they should. Instead they just keep shrinking as a percentage of the parent element.

Here’s a pic showing desktop vs responsive mobile size: http://imgur.com/g9BHLMX

I want the picture to justify centrally and the text to fill the width on mobile view. I thought that’s what bootstrap grids generally do.

Any ideas would be greatly appreciated. I realise it’s difficult without seeing the code of the site.

Yes my theme has bootstrap in it

My theme pulls in bootstrap.min.css in the header. The rest of the theme uses bootstrap and collapses as it should.

Is it something to do with having a grid within a grid, since the other elemets are also bootstrap?

I would really appreciate any help you can offer