Without seeing the plant It sounds like they're sitting in nitrogen rich soil. To much nitrogen will produce lots of lush dark-green leaves growing tall, and may look nice but will delay flowering and produce fewer tomatoes, a very common problem people have over fertilizing tomato plants. Look at the leaf color, healthy plants should have medium green to moderately dark green leaves. Very dark green leaves will mean there is to much nitrogen available.

If your leaves are dark green, not adding nitrogen to to soil for a while is the only thing you can do, and then wait. And what ever you do don't fall for the hype that bloom booster will make flowers, it won't. The high phosphate level in the poison will tie up Iron, copper, zinc and Manganese micro nutrients making them less available and cause a new host of problems you don't want to deal with.