MS SQL Lock on sys tables

Question

I have noticed that certain schema info tables, like for example sys.columns or sys.sql_modules are locked and I cannot query them. When I do, the query runs for ever with no result.

I have tried to find all locks and kill them, but this won't help as I can't see any info on 'sys' through sp_who or sp_who2.

Any tips?

thanks guys! Giorgoc