First of all, I don't see any reason to add your column to a specific position. You can always use the column order as you want for a select statement for example..
Why always inserts the column at the end of the table?
Because it is designed like that?
There is a method to insert a new column in a specific position?
As far as I know, there is no way to do it without rebuilding your table.
From ALTER TABLE syntax for changing column order
Today when you use ALTER TABLE ADD to add a column, a new column is
always placed as the last column. This is far from often desireable.
Often developers and database designers want to keep some logic in a
column order, so that related column are close to each other. A
standard rule we keep in the system I work with is to always have
auditing columns at the end. Furthermore many graphical design tools
encourage this kind of design, both bottom-end tools like the Table
Designer in SSMS as well as high-end data-modelling tools such as
Power Designer.
Today, if you want to maintain column order you have no choice but to
go the long way: create a new version of the table and copy over. It
takes time, and if not implemented correctly, things can go very
wrong.