Oooh, we have lots of pine trees here in south carolina and you tend to see azaleas planted under them.

I have Formosa azaleas (Azalea indica 'Formosa') planted around 2 enormous loblolly pines in my front yard...the azaleas are smothered in blooms right now. The Formosas get very tall and look spectacular growing under the pines and they're evergreen which means they will look good year 'round. Formosas have large, showy pink blooms.
I don't think Formosas are cold hardy to zone 6, but there are many azalea varieties which are, and they prefer shady or filtered shade conditions such as the pine trees provide.

Pine trees suck up alot of water but azaleas don't appear to be bothered by that. I guess that's what so many people use them under pines here in sc. It's one thing you'll have to consider if you want flowers under your pines...competition for water.

If you click on the link below, you will see one of the varieties hardy in zone 6. If you do a search of that site you will find at least a half dozen that are hardy in your zone.

Here is a link that might be useful: azalea link

Also try impatiens- mine did great under a big old pine last year.

I am originally for the Ohio Valley also. You have better soil in the Valley than we do with our VA red clay. I would try Hosta, Ferns, Impatiens and bleeding hearts. Just remember Hosta will attract deer, so plant some boxwood to keep them way.
Happy gardening. TedK

does anyone oppose lilies of the valley? very tough plant. Under my pines I have planted lungwart (pulmonaria), bloodroot (sanguinaria), lilies of the valley, japanese ferns,[and some bulbs which are not showing many signs of success (first season: black tulip, globe allium, wind flower anemones, scilla). I think the squirrels had themselves several nice snacks]. don't forget that impatiens and begonias cannot tolerate dryness, i find them a bit of a pain...oh, i also went with forget-me-nots (myosotis) at the edges of the shade just to experiment. I'd like to find primrose 'denticulata', and plan on hosta, coleus, and japonese anemones. I am z 5 in the mid hudson valley

Azaleas, Azaleas, Azaleas.....then you'll have to find something for color the other 10 months of the year.

Chuckiebtoo

You also might want to consider mountain laurels and some of the more cold-hardy camellias (like the "Ice" or "Winter" series).

Here is a link that might be useful: Cold Hardy Camellias

You could also try some hardy cyclamen. They like it on the dry side. Cyclamen coum blooms in very early spring, cyclamen hederifolium blooms in early summer/fall sending up the flowers first then foliage follows in October.