do they get very dry? they do need plenty of water as they are flowering. if they get too dry the fruit wont set.
do you know which variety you have?
and welcome to GoY.

thank you all.
no they get watered a lot in summer. and i do prune back long shoots. what i can't understand is.. why do other people have these and just let them get on with it.. and they fruit profusely.. mine never have.
i do get plenty of bees in them as well. i might try giving it a good pruning. see if that wakes it up a bit. lol.

Are you actually pruning off the parts which would have fruited?

I think Mg has got the problem sussed. I have a pyracantha hedge in my daughters garden and several in my own and they all flower and fruit like mad. I tend to cut them to shape while the fruit is on them and then give them another quick snip to get rid of any unwanted branches when they start growing again. Can you leave them to grow as they will this year and then when you see the fruit forming you can choose how to trim it back. I tend to cut unwanted branches at any time of year on any plant, if, for example, they are sticking out over a path. Pyracantha is one of my favourite shrubs because it has year long interest and is not fussy as to soil type etc.

The berries form where the flowers are - if you cut any flowering growths off, you won't get berries.
If you're not cutting after it flowers, then, as someone else already said, water could be a problem. Insufficient water when fruit (berries) are trying to form means they simply don't form at all.
Another possibility is an infection in the flowers, usually fungal, which destroys the blossom before its able to start forming fruit, or withers the berries as they start forming. Pyracantha scab is a possibility, but there would be some evidence of this kind of problem though, with blackening on the leaves, sometimes stunted growth, small knobbly growths on the stems, and very small berries which wither and fall before maturing. Lastly, the other obvious one is lack of pollination - but you already say you see plenty of pollinating insects there.

i don't prune when the buds appear on it. but the fruits are very small and withered. and drop off before they even look anything like a berry. they never seem to develop.
i only trim the height slightly.
thanks again all. i might prune it down to the ground hard, and see if that kicks it to life. i have done this to roses and they've flowered really well the following year.

With that information, you're left with two possible problems - lack of water once the berries start forming, or pyracantha scab. The latter overwinters in very small pustules on the shoots of the plant - infected areas should be cut out and a fungicidal spray applied to the whole plant. General symptoms other than problems with the berries will be blackish or dark brownish scabby patches on leaves or stems or both, with some yellowing leaves and premature leaf fall during the growing season, leaving the plant looking rather bare and leggy compared to a healthy one.