Have you ever pruned the pear ( what kind ? ) trees, or the forsythia? Are both growing in full sun?

If you prune at the wrong time of the year (summer or fall) - you would be cutting off the blooms for the spring. Both require full sun for best growth and bloom.

If you've not pruned it at the wrong time as Mike mentioned...1) the soil or location may not suit the plants...get a soil test 2) I had this problem with a wisteria so I did some research online and followed the recommendations and I had beautiful wisteria 2 years later. Forsythia is the same thing...give it a rest for 2 years if you can (don't fertilize or prune). If it doesn't bloom that second spring move it to a more hospitable location.

Anything that is supposed to bloom and doesn't is either not in the right location or you're over doing something.