If it were a deadlock scenario it would be sorted by the database engine (one would be chosen as a victim and be killed) in fairly short order.

You'll want to see what the thread at the head of the blocking chain is doing. If you're using sp_whoisactive then look for the blocking_session_id column and trace along the chain until you find the culprit. Check the sql_text and the wait_info columns to see what that session is running. If you want to open things up that is the session you would kill, but obviously that is a sledgehammer approach and as it sounds this is starting to become a recurring issue so best to get to the bottom of the issue.