Whole grain/Fullkorn plain bread I just can't get it right
I'm losing my nerves with this bread baking. Let me tell you why... I have baked about 5 to 7 multigrain or solely full korn breads and they all turn out to be dense, hard and chewy. I don't know what i do wrong... I have followed different types of recipes, bought different type of flours, tried fresh and dried yeast, let it rise for different times, different knead times...
But the result is always very similar. I mix the ingredients of the bread (mainly fullkorn flour, water, tbsp olive oil, yeast, salt and sugar) and knead it all for 10 minutes. I let it to rise after kneading for about 90-120 minutes, the dough becomes nicely airy and big. Kind of the way that i was hoping to get out. However all recipes state that I had to knead it a bit again and make it in a roll to add it to greased bread oven form, and let it rise for another 60 minutes. the rising continues but it looks already more dense again. The sauna (when it's off) is about 35 degrees and i let my bread rise there because it's the only place i could think of that is consistently warm... but I also tried to put the bowl with dough on a hot water pan covered with a dish drying towel. After the second rise I basically bake the bread off in about 30 minutes in the oven.
I think very straightforward and as described in many recipe books i have. The funny, yet annoying, thing is that my sweet breads with almond paste, raisins, currants and what not succeeds everytime i make it and is more poofy, could still be a bit more though, and very tasty. There is no fullkorn flour in that recipe though. But because i want to have some dietary fibers in my bread I would love to succeed to make a nice fullkorn bread. I would like to avoid additives, or flour enhancers and i typically use only organic products. Can anyone point me out in the right direction or give me some hints on what to improve next...
I recently also got a bread baking machine, eventhough the bread is a bit more airy (still not enough to my taste) it's really hard and chewy for some reason as well. (also full korn flour included.) If only my fullkorn bread could look like this: http://shop.bakkendebakkers.nl/media/catalog/product/cache/1/image/9df78eab33525d08d6e5fb8d27136e95/v/o/volkoren.jpg 
Thanks in advance for any help or advice!