I happened past here and noticed that you haven't received a reply so I will say a word or two. I believe that the U of IL cooperative extension service, which has a web site, is the place to check first. Also, I think Morton Arboretum may test soil.

The bottom line for most of the area though, is that, if you live really close to the lake, you will have sandy soil of neutral ph, but nearly everywhere else is alkaline clay. In general, if you have clayey soil, adding organic material such as peat moss, pine bark fines, partially composted soil conditioners, etc. - all available at nurseries in the area - will help to counteract the alkalinity and also lighten the heavy clay.

When I was a kid, I lived about 4 blocks from the lake and was used to very loose, sandy soil. A couple times, the street outside my home actually buckled in summer (once with a car in it). I was shocked to move to the NW suburbs 20 odd years later in August, and find that I couldn't even get a shovel into the ground, the clay was so hard and dense. I have been battling it since then, I might add, with pretty good success.