First things first - if you want a single row, you'll need to adjust these divs to be width "3" each or reduce the total number of them. Keep in mind that 12 is the key number for the Bootstrap grid system.
Additionally, grouping the columns within a .row class helps control the margins on the sides. The padding is actually contained INSIDE the divs, not between them. The example below shows three adjacent divs within a row, each with left/right padding of 15px:
<div class="container">
<div class="row">
<div class="col-lg-4"></div>
<div class="col-lg-4"></div>
<div class="col-lg-4"></div>
</div>
</div>
The .row class has a -15px margin on both sides, ensuring that the side divs align with the edges of the parent container. Also, remember that using container-fluid will stretch the parent div across the entire viewport.
In conclusion, Bootstrap .col-* divs do not have padding between them but rather inside them, unless overwritten by custom CSS rules.