Weird scroll bar I want to get rid of

I don’t know what I’ve done, but this weird horizontal scroll bar has appeared under certain sub headings on our site. You can see it in the attached screenshot under “Contact us” and “Send us a message.” It appears to serve no purpose but scroll to the left of the heading (which, of course, is nothing but white space). These scroll bars have appeared a few other places on the site. Can you please tell me what I’ve done to make them appear and, more importantly, how to get rid of them? Thanks!