sys.dm_exec_requests will show you the immediately running queries that are experiencing blocking. You can combine that with sys.dm_exec_sql_text to get the query and sys.dm_exec_query_plan to get the execution plan.

There is nothing in SQL Server that automatically gathers this information out of the box. You can set something up though. Extended Events offers mechanisms for doing exactly this. Here's an example[/url] (I haven't tested this one personally, but it'll get you started).