FLC CONFUSED CTLR'S VECTOR BY 100 DEGS.

Narrative

WE ARRIVED AT IAD ON FLT A; AND WENT OUTBOUND ON FLT B. WE HAD APPROX 20 MINS TO PREFLT. THIS MAY HAVE HAD AN AFFECT ON WHAT HAPPENED NEXT; AND THE FIRST 10 MINS OF FLT. AFTER TKOF FROM RWY 30; WE WERE GIVEN SEVERAL HDG CHANGES; THEN THE LAST CLRNC WAS TO CLB FROM 10000 FT TO FL190; TURN L TO HDG 050 DEGS AND INTERCEPT (AS I HEARD IT) THE 217 DEG RADIAL OFF OF SMYRNA. BTWN THE CAPT AND I; WE WERE QUESTIONING THE CLRNC BECAUSE THE CAPT HEARD; HDG 150 DEGS AND HAD ALREADY STARTED A R-HAND TURN TO HDG 150 DEGS. THE CTLR WAS VERY BUSY; AND WE COULD NOT CONTACT HIM. WHEN HE DID CALL US; HE GAVE US A FREQ CHANGE. WHEN I CONTACTED THE NEW CTLR AND QUESTIONED OUR CLRNC; HE TOLD ME TO STAND BY. THEN HE CAME BACK AND GAVE US AGAIN; ANOTHER FREQ CHANGE. WHEN WE GOT TO THE NEW FREQ; THE CTLR HAD RAISED HIS VOICE; AND SAID TURN TO HDG 050 DEGS AND INTERCEPT THE 271 DEG RADIAL INBOUND TO SMYRNA (EMO) -- IT IS DEPICTED ON THE CAPITOL 4 DEP. WHEN WE WERE GIVEN THE CLRNC; AND WANTED TO CONFIRM IT; WE WERE UNABLE. TO GIVE US MULTIPLE FREQ CHANGES; AND TO TELL US TO STAND BY MADE THIS VERY CONFUSING AND STRESSFUL. IF THE CTLR WOULD HAVE MENTIONED IT WAS ON THE SID; IT WOULD HAVE CLARIFIED EVERYTHING. I LEARNED FROM THIS EPISODE; AND NEST TIME WILL REVIEW THE SID MUCH MORE CAREFULLY TO TRY AND EXAMINE ALL THE POSSIBILITIES WE COULD GET.