2 IN C172 AND 3 FAA CTLRS AND STILL A QUESTION OF ASSIGNED ALT.

Narrative

THE FLT WAS AN IFR FLT IN VMC FROM DPA TO LAF. I RECEIVED MY CLRNC FROM DPA CLRNC DELIVERY. AS THE RTE WAS COMPLETELY DIFFERENT FROM WHAT I HAD FILED; I ASKED THE CTLR TO REPEAT IT. THE CTLR REPEATED ONLY THE RTE OF FLT INFO OF THE CLRNC. I READ BACK THE RTE TO THE CTLR; BUT OMITTED THE REMAINDER OF THE CLRNC (ALT; DEP FREQ; SQUAWK CODE; ETC). THE CTLR REPLIED; '...READBACK CORRECT.' BEFORE TKOF; THE CTLR ISSUED A NEW DEP FREQ AND I CONFIRMED THE XPONDER CODE. I DID NOT CONFIRM THE ALT I WAS SUPPOSED TO CLB AND MAINTAIN; WHICH I THOUGHT WAS 4000 FT MSL. I WAS CLRED FOR TKOF AND TOLD TO '...TURN R HDG 160 DEGS.' AFTER TKOF; I WAS TOLD TO CONTACT CHICAGO DEP. MY SAFETY PLT CONTACTED DEP AND RPTED; '...CLBING THROUGH 1200 FT FOR 4000 FT.' THE CTLR ACKNOWLEDGED 'RADAR CONTACT' BUT SAID NOTHING OF THE ALT MY SAFETY PLT RPTED WE WERE CLBING TO. WE CONTINUED ON HDG 160 DEGS AND CONTINUED TO CLB. AT ABOUT 3800 FT MSL; DEP ASKED WHAT ALT I WAS CLBING TO AND 'WHO ASSIGNED 4000 FT?' I STILL DO NOT KNOW WHAT ALT I WAS ORIGINALLY ASSIGNED. THIS COULD HAVE BEEN PREVENTED BY CLRNC DELIVERY ASKING ME TO READ THE ENTIRE CLRNC BACK BY CHICAGO DEP CONFIRMING MY ALT ASSIGNMENT OR; MOST IMPORTANTLY; BY MY ASKING ANY OF THE CTLRS TO CONFIRM MY ALT CLRNC IN SPITE OF EMBARRASSMENT.