Yes, you can find cell value in checkbox changed event using row index or the row itself.
Check following-
CheckBox cb = (CheckBox)sender;
GridViewRow gr = (GridViewRow)cb.Parent.Parent;
string cellvalue=string.Empty;
cellvalue = gr.Cells[0].Text;
Label lbl=(Label)gr.FindControl("YourLableId");
cellvalue=lbl.Text;
Hope, it helps :)