Q.My Tree Has Plenty Of Flowers And When It Produces They Get The Size Of A BB And Fall Off
It produces flowers every year plenty when the plums start to grow they get the size of a BB and then they start falling off

Certified GKH Gardening Expert
This is normal, for the most part. They will produce many more than they can sustain on the tree. Once the majority of the fruit drops, what is left should mature.
If none of the fruit stays on to mature, I would look at soil nutrient levels. The tree may be lacking in Phosphorus and Potassium, or may have too much Nitrogen in the soil. This will cause the symptoms that you are seeing.
These articles will help: https://www.gardeningknowhow.com/edible/fruits/fegen/reasons-for-small-hard-fruit.htm
https://www.gardeningknowhow.com/edible/fruits/plum/plum-trees-not-fruiting.htm
https://www.gardeningknowhow.com/edible/fruits/plum/growing-plum-trees.htm