Four years illegal presence (presumably you were over 18) is enough to trigger the ten year bar. Applying for a green card if you qualify is "current" (i.e. only moderately slow). Yes, they will tell you why (the fact you were subject to a ten year bar due to prolonged illegal presence would be it). You can apply for a waiver to the time bar. Getting decisions on waivers of inadmissibility is running 20+ months right now.

