Most frozen foods ARE good for your health. Of course, fresh is better, but if you can't get/afford fresh, frozen is next best. Be sure to watch package ingredients and make sure that the only thing in the package is vegetables/fruit. Same goes for frozen fish......
Always opt for veggies/fruits in the following order: fresh, frozen, canned. Best to avoid canned veggies, as they often contain WAY too much salt and other preservatives.
Yes. Frozen foods are not good for health. Keep eating fresh always and the last option is frozen foods.