You should not be able to touch the hoses at full operating temps. Pull the heater core hoses and run a garden hose in one side. Ill bet you will see mud coming out the other hose. This technique should always be employed during scheduled flushings. The pump doesn't have enough azz to remove the debris from the heater core, purposely because the heater cores generally cant handle higher pressures and usually run a restrictor orifice in the system as well... So be careful with the garden hose. Does this truck have a coolant bypass or shut off valve on it? This would be a vacuum operated valve which is signaled on or off from the temperature control on the dash. The purpose of this valve is to shut off the supply of hot coolant to the heater core when the AC system is on to assist in AC efficiency. This valve could be bad. Trace the heater core lines. If you see the lines going into the firewall chances are you dont have one or its under the dash??? Get a diagram of this system from the dealer if your not sure. Chances are it has one. Or call a parts store and ask for one. If they think your crazy then it probably doesnt. Sounds like you have a restriction or a bad bypass valve.
Regular maintenance on the cooling system usually prevents this type of trouble. Coolant gets acidic after a while and self destructs itself if not regularly serviced. "Mud" also settles to all the low spots or low pressure spots further reducing efficiency. Your cap sounds bad as well. Have the cap and the system pressure tested. Purchase PH strips from parts store and check the system PH.
Did you verify that the passenger side foot well is dry? If wet the core is already gone.

 

thanks all ive got an appointment to have it reverse power flushed monday. ill see where it goes from there.

 

got the truck antifreeze flushed today but it was a warm day so im gonna check the results in the morning. will advise of results tomorrow.(if i remember lol)