This is often a problem after the holidays, or some other extended break. If that occurs, there's is nothing anyone can do. It gets really nasty if other users start stacking up behind you, all waiting. Particularly true after semester breaks and similar situations. Internal conflicts between application programs are an occasional problem.
Programs can compete for a variety of resources.
Some programs may not play fair, others just play by their own rules. Most programs just plod along going about their business. Some times this conflict causes one or more programs to stop, waiting for each other to finish. CICS will usually work its way out of this situation by killing off some of the problem programs.