Matrix To Single Column

I have an array of data with column headings and changeable row "item names"
in the left most column. The intersecting matrix of data contains quantity
values at the intersection cells of column and row headings. I need to
automatically reorganize the data as a list in a column with the row "Item
Names" at the left but and repeated as necessary but instead of the
additional columns of quantity values, I need to have this data listed in a
single vertical column along with an additional column with the original
column header that corresponds to the quantity value. I think there must be
some kind of lookup function to do this but I can't find the right way to do
it.