To trace the locks, you can use the DB2 Monitor, adjusting it for looking at lock specifically. You can also use a free third party tool that might
help a little, it can be found at: http://chuzhoi_files.tripod.com/index.html
Also you might want to look at the SQL and try to limit the amount of locking. For SELECT statements that are only interested in looking at data and not modifying it, add the "FOR READ ONLY" clause to prevent share locks being issued. Also keep Units of Work (UOW) as short as possible. Never do human I/O during a UOW. Issue COMMITS more frequently to keep UOW short (but not so as to mess up transactional logic)
For more info on DB2 locking, search the Web where you can find numerous resources that should be able to expand on this.