Looking at the snippet provided, the div with the class divSection is organized in groups. These divs should remain below the text (text 1, text 2, text 3) that are within the div with the class divSection. Adding a margin to divSection is an option, but I prefer it to have a margin of 0 when there's no content inside the div.
.divSection3, .divSection7{
height: 38px;
background-color: rgba( 26, 26, 26, 0.7);
}
.section{
text-align: center;
padding-top: 13px;
display: flex;
flex-basis: 100%;
align-items: center;
text-transform: uppercase;
}
.section::before,
.section::after {
content: "";
flex-grow: 1;
background: rgba(255,255,255, 0.35);
height: 1px;
font-size: 0px;
line-height: 0px;
margin: 0px 8px;
}<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.1.1/css/bootstrap.min.css" integrity="sha384-WskhaSGFgHYWDcbwN70/dfYBj47jz9qbsMId/iRN3ewGhXQFZCSftd1LZCfmhktB" crossorigin="anonymous">
<div class="container mt-5">
<div class="row">
<div class="col-12" style="background-color: red;">
<div class="row">
<div class="divSection3 col-lg-12">
<div>
<h6 class="section text-white ml-2 mr-2 ml-lg-0 mr-lg-0">Title 1</h6>
<div>
<h5>texto 1</h5>
</div>
</div>
</div>
<div class="divSection7 col-lg-12">
<div>
<h6 class="section text-white ml-2 mr-2 ml-lg-0 mr-lg-0">Title 2</h6>
<div>
<h5>texto 2</h5>
</div>
</div>
</div>
<div class="divSection3 col-lg-12">
<div>
<h6 class="section text-white ml-2 mr-2 ml-lg-0 mr-lg-0">Title 3</h6>
<div>
<h5>texto 3</h5>
</div>
</div>
</div>
</div>
</div>
</div>
</div>This is how it should appear: