Lawn Diagnosis?!?

[clayslandscape]

I built my house two years ago on a lot that was heavily covered in pines for hundreds of years. The front yard I have growing great as you can see in the photo. The back yard grows in and seems to get to a point where it does nothing more. The last two falls I have overseeded the back yard with a mix that had about 20% annual rye and it comes in great but of course with the heat of a Virginia summer it dies. This year after core aeration i reseeded without any rye and the grass has all germinated everywhere but it has been one month and the grass has stalled at a very young stage... What should I do?

Starter fertilizer has been added, plenty of lime... should I aerate again this fall? Is it beneficial to ever aerate more than once a season?