Broken responsiveness

[ghost]

Hello there,

I am making a site using bootstrapWP child theme, but I keep breaking the responsiveness. What is the best way to avoid this? I have made divs within a span, is this allowed?
example:

is this kind of thing allowed or is it this kind of practice that is breaking my responsiveness? I am also using position: relative; on elements to move them around.

Any help very much appreciated.

All the best

Harry

p.s. a link to my site: http://rookdesigns.co.uk/