Problem with string concatenation in PHP + HTML and elements alignment problem

I have the following 2 problems the first is here

disappearing checkbox

It appears when I try to put a PHP variable into div via this line of code:

wrong string syntax

Could you please tell me where the error might be? The result in the source code is

HTML result

I am trying to left align certain checkboxes (and the spaces between them) which are bothsituated in the $partsSearchingArgument variable and I put the variable in div, but it does not work properly. The $secondVar element holds the whole of possible elements (textareas, checkboxes etc).

Could someone tell me how to resolve the syntax problem and the alignment problem as well? dislocated checkboxes