This should give you a rough idea of what to do.
This is code I have used with an access db to select specific data into text boxes related to the selected Datagridview row.
private void DGReview_CellClick(object sender, DataGridViewCellEventArgs e)
{
conn.Open();
OleDbCommand cmd = new OleDbCommand();
cmd = conn.CreateCommand();
cmd.CommandText = @"SELECT * FROM [Table] WHERE [Variable] ='" + DGReview.SelectedRows[0].Cells[0].Value.ToString() + "'";
cmd.ExecuteNonQuery();
DataTable dt = new DataTable();
OleDbDataAdapter adapterA = new OleDbDataAdapter();
adapterA.SelectCommand = cmd;
adapterA.Fill(dt);
Object a = dt.Rows[0]["Variable"];
textbox.Text = Convert.ToString(a);
conn.Close();
}
Where as the method is DG_Review_CellClick yours would probably be checkbox_CheckedChanged