Many whole-grain and multi-grain products include whole flax seed (breads, cereals, and even tortilla chips). However, we don't get the benefit of its omega-3 fatty acids and phyto-chemicals because they aren't broken down in our digestive system. (Check your poops the next time you eat a serving of Red River Cereal.)
Ground flax seed provides digestibility so you get the health benefits. But because of its high oil content it's liable to go rancid before you use it up. So it's best to buy flax seed in bulk, grind it in a coffee grinder, and store the ground seed in the refrigerator or freezer, or else grind only the amount you need.
One tablespoon of ground flax seed provides 1.6 grams of omega-3 fatty acids.
Ground chia seed, on the other hand, does not deteriorate after a while (and grinding helps a lot to keep the whole seeds from getting caught in your teeth). One tablespoon, whole or ground, provides 3 grams of omega-3 fatty acids.