Using the below query you can easy to get column names from the Information schema in SQL server.
select COLUMN_NAME
from INFORMATION_SCHEMA.COLUMNS
where TABLE_NAME = N'YourTableName'
If you want result as comma , split
Select Stuff(
(
Select ', ' + C.COLUMN_NAME
From INFORMATION_SCHEMA.COLUMNS As C
Where C.TABLE_SCHEMA = T.TABLE_SCHEMA
And C.TABLE_NAME = T.TABLE_NAME
Order By C.ORDINAL_POSITION
For Xml Path('')
), 1, 2, '') As Columns
From INFORMATION_SCHEMA.TABLES As T where T.TABLE_NAME='YourTableName'