Should be low pressure A/C line be cold coming from the firewall?

My wife had been driving the truck and said it wasn’t very cool and asked me to check it when I got home. When I put a gauge on it the pressure was somewhere around 45. I tried adding some refrigerant, but I don’t think it took any, but I felt inside the truck then and it was pretty cool.
I said this is the low pressure but upon looking again, I think it is the high. It goes from the bottom of the condenser across the front of the truck and then along the passenger fender.
The area in the picture is between the air filter box and the fender. This is the area that changes temperatures, right between my fingers.

If you look really close, you can barely see the indentations I was referring to.
My wife said it felt nice today.

Does that mean the orifice is stopped up or is this temperature difference normal? It is extremely hot towards the condenser and pretty cold from that point to the firewall? If so, can I pull that line and flush it, then vacuum and recharge the system or replace the line? Either way how do I know how much oil to outback in the system?
I guess I probably need to get a set of gauges to check the high and low pressures.

I might rent a set of gauges from O’Reilly or AutoZone this week and I will let you know what the gauges show. So, you are saying the orifice tube isn’t stopped up?
Thanks for the replies.