Using a for loop iterate the GridView.Rows collection to see whether the Checkbox is checked. If it is checked, then retrive the data and insert/update into another table.
foreach(GridViewRow gridRow in GridView1.Rows)
CheckBox chkBox1 = gridRow .FindControl("yourCheckBoxId");
//Write code to retrieve the values from GridView row using gridRow.Cells collection and insert/Update into another table
now in this case wht you can do use the above sample code
create one lable (any name ) and udpate you'r code with that lable
and on Display the inbox item you can query such that (show item without label)