Cherry tree not producing any cherries, when it did produce they seemed to be diseased. Sprayed tree with a spray that the nursery told me to buy, no help. Called the Ministry of Agriculture and they said to call TMGs.
There are a number of reasons why your cherry tree may not be producing any cherries. The cold spring we had this year could meat that while your cherry had blossoms, it did not set fruit. In that case the problem may not occur again next year. Although, as your tree has not been developing fruit over number of years, the weather is unlikely to the be the problem.
You indicated that your tree is healthy, and getting small fruit which is not developing. As the tree is a sweet cherry tree it needs another cultivar of a sweet cheery for pollination. The small undeveloped fruit is not conclusive evidence that the tree is in fact being pollinated and you should consider planting another tree, if there are no others in your neighbourhood.
Another possibility is the wrong nutrients in the soil. Too much nitrogen may result in excessive leaf and tree growth over fruit production. However the tree does need nitrogen to develop. A soil test can determine whether your tree is getting the right mix of nutrients.
While your tree is healthy, you should consider whether there are any changes to be make to its growing conditions. Here are link to a previous TMG question outlining good cultural practices for fruit trees (https://www.torontomastergardeners.ca/index.php/askagardener/no-fruit-on-my-apple-tree-in-my-back-yard/) and to an Ontario Ministry of Agriculture and Rural Affairs release on Fruit Trees in the Home Garden (https://www.omafra.gov.on.ca/english/crops/facts/fruit_home.htm)