You can pass multiple values as query string using Response.Redirect() method as
protected void LinkButton1_Click(object sender, EventArgs e)
{
string id = (string)(Session["TID"]);
string paid = (string)(Session["PAID"]);
Response.Redirect("print_page.aspx?TID=" + id+"&PAID="+paid);
}
Use "&" to add the query string parameter.