I now have heat from both sides.
I did as AaronOregon suggested and now I have a ton of heat from both sides!
I have only single zone heat so, AaronOregon suggested to remove the glove box and reach behind and feel if the actuator was working when moving the dial from hot to cold. I felt that it was working. So I decided to take his next bit of advice and back flush the heater core and re-fill the system.
What I did was, undo the heater core hoses from the engine and gently back flush the heater core catching the first bit with a bucket. I didnt have any fancy gear to to do this, I just had a hose nozzle that had a rounded brass end that snuggly fit into the heater hose end. I also alternated which hose I ran water through to cycle it back and forth a few times. I then reconnected everything and left the radiator cap off so that I could eliminate air and fill the system to capacity with new fluid. To my surprise, I had strong heat from both the drivers and passengers sides. I test drove the truck last night to make sure nothing was wrong -leaks, overheating etc.
Before I started the truck up I checked that the coolant tank showed the correct level at the cold mark. It was fine, so I was on my way. This AM the outside temp at 42 and I had toasty heat!
Thanks to everyones contributions to help trouble shoot.