Transpose multiple columns into 2 column and single row to multiple row in sql
There's a T-SQL construct called UNPIVOT which is designed for this. But in my experience, you'll have more luck with APPLY as per my code below:

SELECT *
FROM YourTable t
CROSS APPLY
    (SELECT 'Col1', Column1
    UNION ALL
    SELECT 'Col2', Column2
    UNION ALL
    SELECT 'Col3', Column3
    UNION ALL
    SELECT 'Col4', Column4
   ) u (columnName, Value)
  ;