Unable to loosen and unscrew kitchen faucet screen...

The first thing to check is the filter screen inside the nozzle. There should be a ring that you can unscrew right where the water comes out. You will probably have to use a pair of pliers to loosen it. Use an old dishcloth or rag between the ring and pliers. This will protect your shiny faucet from being scratched! Once the ring is off, look inside it. There should be a metal screen inside with very fine mesh. It will come right out, but you may have to use the tip of a knife to pry up on one edge to get it started. Most likely, it is clogged with sediment. Clean it by holding the clogged side down under a running faucet. This is backflushing. Remove any remaining sediment with a fine brush and reinstall by reversing the directions above. Some people just never put them back in, preferring the stronger flow of water. Good luck!

There are several of things that could cause that but the first thing I would do is unscrew the little screen thing at the tip of the faucet.
If you then get good flow, clean it and put it back on.

water flow on my kitchen faucet is very low YouTube

How did you resolve the problem of removing the spout assembly? We also have a Price Pfister 34 series kitchen faucet and are trying to replace the diverter. Like you, we have removed everything down to the spout assembly, which will not simply lift off. We have tried letting it sit overnight with WD40, thinking it would loosen it up. No such luck. Then tried using white vinegar, thinking maybe there were calcium deposits holding it on. No luck. Please tell us that you were successful and how you got the victory over this stubborn thing!

I just fixed our Nannini from Costco. The screens were plugged with plastic filings coming from our water lines. On our faucet there is more than one screen.
The pull out faucet has the basic screen like 99% of the taps out, right on the end. It comes apart by first unscrewing it from the handle and gently (gently) nudging the screen out with a sharp object such as a pairing knife.
Then in the handle was where the problem lay with mine. There was a plastic knob which is recessed in the handle. Leave the hose connected and pull it out until it is stretched or have a helper, then press on that small knob, pull and the whole inside will pull out. There is another filter in there. I was able to take mine apart and clean it, yes it does pop apart but be careful. In assembling mine I just left out the second filter totally.
I guess in hindsite you wouldn't have to actually take the whole handle apart if one has a 90 degree tool to pull out the yellow plastic piece. I used an allen wrench and pulled. Cleaned it with a small needle.

Works better than new!

Aireator on end of faucet where water comes out has water saver inside with screen,unscrew and clean plus flush faucet,should take care of Richie Rich

Yes, the aerator (where the water comes out) can be unscrewed and removed from the faucet. I remove these and clean them out on a regular basis. If the aerator won't unscrew by hand, place a washcloth over the aerator (to prevent scratching) and carefully turn it with a pair of pliers. (Screw direction to loosen: Looking down on faucet, with pliers to the right-hand side, pull them toward you.) Make sure the rubber washer is properly placed in the top of the aerator after you have cleaned it out and you go to screw it back on. You normally don't need pliers to put it back on, as these are meant to be screwed on hand-tight. There might be several little parts inside the aerator to take apart and clean out, so be very careful to put these parts back together the same way they came apart. I find a toothpick is often useful to clean these out, as well as a cup of water to rinse them in.

filter screen is usually just under where the water comes out. Cover drain so any parts do not get lost down drain. Just unscrew it counter-clockwise to loosen it up. Remove screen and clean by flashing water in bathroom sink until screen holes are clear. then re-install and tighten in clock-wise direction. All done after you check that water comes out again.

Silly question, but did you turn the shut offs back on after installing? If so, the aerator is probably clogged (the screen on the faucet). Unscrew it and clean it out. Good luck

On the tip of the faucet there is a screen on it, remove the screen by unscrewing the it counter clockwise use a pair of pliers with a rag on it to keep from scratch the faucet end then if you have a large volume of water you will have to clean the screen out by flushing it out backwards and using a tooth pick to get out any particles yo can get out of the screen. there is the possibility that the faucet control handle is defective to but would do the screen test first.

If it only the kitchen faucet, then the screen inside is clogged. Remove the filter by unscrewing the part where the water exits the faucet. Pay attention to how the pieces come out so as to replace in same order. there will be small debris that has to be removed then just replace in same order it came out.