I cannot express enough how important it is that you separate the yard from the field right now. It is critical.
Pile work, is yard work.
Marks, are field work.
DON'T MIX THEM TOGETHER!!!!!!!!!!
The yard is full of pressure. You are teaching the dog how to deal with it, and work through it.
When you get through it, you can leave all that "pressure baggage" in the yard, and bring the skills that you taught the dog in the yard, into the field.
But, you can't do that, if you did yard work in the field, and field work in the yard during basics.
Have a place that you do yard work, and do your yard work there.
Have a DIFFERENT place that you can work on marking, and do you marking sessions there.
They don't need to be miles apart. As long as the dog can separate the two "worlds" it's what you want.
And quit throwing marks from the dog's side. Get a helper to throw for you. Or, sit the dog, walk out and throw it yourself.