Power steering gets hard when turning and it feels like the fluid isnt flowing the way it should

Hello, There is a reservoir line coming out of the bottom of the reservoir tank. This line goes to the front fluid cooler under the drivers' side front bumper. The line has both metal and rubber on it and the line mounts to the frame with plastic clips. The plastic clips hold moisture and salt next to the metal part of the line and it rusts. The frame will hide the leak and the line will draw in air making foam inside the pump. Check this line from the reservoir to the cooler.

Next, as the original owner of a 1999 model, I received a Service notice about the tie-rod ends. It said a Mechanic should separate the tie-rod ends when lubing the truck to check for rust in the socket of the tie-rod end. These are sealed fittings from the factory, Ford could have included fittings in the first place. I don't see any Mechanic doing the procedure without replacing the end.
So your tie-rod could need Service.

Check upper and lower ball-joints, rust can make the steering hard on any vehicle. If you decide to change out the pump, check whether the new pump comes with the pulley. Some of the pulleys require a special tool you can borrow from an Autoparts store and some pulley tools are meant to be used while the pump is still on the truck.

Steering and turning the wheels is also dependent on the front-end alignment. The alignment is something you can not do yourself, but the Mechanic would inspect the different things I mentioned for the ball-joints and tie-rods ends. To save money, you could replace all the ends yourself, by counting the number of turns each tie-rod end takes to come off. Then replace the end with the same number of turns. You would be close enough to drive for an Alignment.

I hope I have provided very good information for fixing your truck. Make sure the front tires are inflated well and have the heavy stuff done by someone with the right tools.