Can't really make much suggestion without knowing more about where you are located, what kind of weather and conditions your tomatoes are growing in and how you've been caring for them. Much of the country has had cool wet season, but Texas and other places have had months of triple digits. Makes a big difference...
In the meantime some possibilities include too much nitrogen (if you are fertilizing) which encourages the plants to grow tall and leafy, but discourages fruit production. Are your plants getting what they need, i.e. full sun, consistent water, plenty of nutrients? Are you having triple digit temps? tomatoes absolutely will not ripen at all once temps hit triple digits. The lycopene and carotene that are responsible for the red color break down. The plant gets heat stressed.
In the meantime here's a nice little piece about it:
"Why does it take so long for tomatoes to ripen? There are several factors that affect ripening, including amount of sunlight, optimum temperatures, excess plant growth, lack of water, too much water, or too much fertilizer. It takes a standard-size tomato 40 to 50 days after blossom set to reach maximum size. The larger the fruit, the slower it will ripen. Therefore, late planting can cause tomatoes to ripen later than expected.
If the plant has heavy fruit, it will take a lot of energy from the plant and can delay the whole crop turning red. Tomatoes need sunlight to ripen. Plants with excess plant growth can reduce exposure of fruit to the sunlight and delay ripening. If this is the case, remove some of the vines to expose fruits.
Temperature is crucial to tomato fruit ripening. Red tomato pigments, lycopene and carotene, are produced between 50 to 85 degrees Fahrenheit. These pigments are necessary for the ripening process.
The optimum temperature range for ripening tomatoes is 68 to 77 degrees Fahrenheit. Extreme heat or cool temperatures will delay ripening. The longer temperatures stray from the optimum, the more stress to the fruit." https://www.illinoistimes.com/gyrobase/Content?oid=oid%3A8194
If you are desperate, you can put a paper bag over the fruit and band it around the stem. This holds in the ethylene gas, helps it ripen.