There are some small problems which follow to the problem.
The first problem. You should move the lines where you call navGrid and gridResize inside of success handler. So the navigator and the resizing element of the grid will be created after ther grid will be created.
You uses recordpos: 'left' which place the text like "View 1-2 of 4" which are typically of the right part of the pager on the left part. Then you called navGrid with any additional option. So the position: 'left' will be used per default. If the case the navigator bar will be placed under the text like "View 1-2 of 4" and one will don't see the navigator icons.
You can fix the problem in two ways. Either you can use position: 'right' option
$("#myjqgrid").jqGrid('navGrid','#Pager',{position:'right'});
In the case one will receive the demo:
or you can remove fix height of the pager with the code
$('#Pager').css("height","auto");
see another demo:
One more option is just remove recordpos: 'left' option and receive the standard navigator and pager layout (see here):
