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

If you can take pics it will help. yes, the low sideline from the firewall should be cold when the system is working correctly. Is the A/C not working or what seems to be the problem?

https://www.2carpros.com/articles/car-air-conditioner-not-working-or-is-weak

Please run down this guide and report back.

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.

I believe that is where the orifice tube is.

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.

Yep, you need a set of gauges, check Amazon. Also, yes, the temperature variance is normal on either side of the orifice tube. Only install more oil if oil is removed, you will need to estimate this amount. Please let me know what happens.

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.

Or it could be plugged or partially plugged which means the compressor is coming apart. It wouldn't hurt to remove the line and blow through it backwards to see what comes out the other side.