In our electrical panel we have 2 AFCI breakers next to each other. One is for the master bedroom the other is for 2 guest bedrooms. Each of these breakers is warm to the touch. We have had no electrical problems in either room and it has never tripped. I just thought it was strange that these breakers would be warm while the others are not. Is it normal for a AFCI breaker to be warmer than a regular breaker?

Yes AFCI breakers will feel warm, due to the small electronic board inside that actually does the work of detecting arc currents. This heat should be only warm and will not be any problem.