PLT OF A PIPER PA28 WAS ADVISED BY APCH CTLR OF BEING OFF COURSE AND THEN GIVEN A HDG WHICH THE RPTR BELIEVED TO BE A VECTOR TO BACK ON COURSE. AFTER RPTR TURNED BACK INBOUND OFF OF THE GIVEN HDG; THE CTLR QUESTIONED RPTR AS TO WHY HE HAD NOT MAINTAINED HDG.

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I WAS ON A TWR ENRTE IFR FLT PLAN FROM SNA TO LGB. THE WX WAS VMC (VISIBILITY 10 MI; SCATTERED CLOUDS AT FL250). THE SOCAL CTLR INSTRUCTED ME TO FLY A HDG OF 310 DEGS TO INTERCEPT THE LGB NDB APCH COURSE AND TO MAINTAIN 1600 FT UNTIL ESTABLISHED. HE CLRED ME FOR THE NDB APCH. SHORTLY AFTER BECOMING ESTABLISHED ON THE APCH COURSE INBOUND; FLYING A HDG OF 301 DEGS WITH THE ADF NEEDLE POINTING TO 0 DEGS; THE SOCAL CTLR CALLED ME AND ASKED IF I WAS FLYING THE NDB APCH. HE STATED THAT HE SHOWED ME N OF THE CTRLINE. I REPLIED THAT I WAS FLYING THE APCH AND THAT I SHOWED MYSELF TO BE ESTABLISHED ON COURSE. HE THEN TOLD ME TO FLY A HDG OF 270 DEGS. I TURNED TO A HDG OF 270 DEGS AND MAINTAINED THAT HDG UNTIL THE ADF NEEDLE ROTATED TO A DEV ANGLE OF 30 DEGS TO THE R; A READING THAT INDICATED THAT I WAS ON THE CTRLINE OF THE NDB COURSE INBOUND TO THE FAF (BECCA). I TURNED TO THE INBOUND HDG OF 301 DEGS AND CONTINUED TO TRACK THE COURSE WITH SMALL HDG CHANGES. SHORTLY THEREAFTER; THE SOCAL CTLR ASKED ME WHAT MY HDG WAS. I REPLIED THAT MY HDG WAS 290 DEGS. THE CTLR REPLIED THAT HE HAD GIVEN ME A HDG OF 270 DEGS. I RESPONDED IN THE AFFIRMATIVE AND ADDED THAT HE HAD GIVEN ME A HDG OF 270 DEGS TO REJOIN THE CTRLINE OF THE APCH INBOUND AND THAT I HAD BEEN CLRED FOR THE APCH. HE DID NOT RESPOND TO THIS. SHORTLY THEREAFTER; THE CTLR INFORMED ME THAT HE SHOWED ME RE-ESTABLISHED ON THE CTRLINE AND INSTRUCTED ME TO CONTACT LGB TWR. I DID SO; AND THE TWR CLRED ME TO LAND. I RESPONDED BY ASKING THE TWR TO CANCEL MY IFR FLT PLAN AND INFORMED THEM THAT I WISHED TO FLY A VFR MISSED APCH. THE TWR APPROVED MY REQUEST AND I EXECUTED THE MISSED APCH. THE FLT CONTINUED UNEVENTFULLY UNDER SOCAL CTL WITH A PRACTICE VOR A APCH TO FULLERTON ARPT FOLLOWED BY A PRACTICE ILS APCH AND LNDG AT SNA. MY APPARENT HDG DEV (IE; REJOINING THE NDB APCH INBOUND FROM THE 270 DEG HDG GIVEN ME BY THE SOCAL CTLR) COULD HAVE BEEN AVOIDED BY BETTER COM BTWN MYSELF AND THE CTLR. THAT IS; IF HE INTENDED HIS INSTRUCTION TO FLY A HDG OF 270 DEGS TO BE FOR THE PURPOSE OF BRINGING ME BACK TO THE CTRLINE OF THE APCH (AS I HAD ASSUMED BECAUSE I HAD BEEN TOLD PREVIOUSLY TO INTERCEPT THE APCH COURSE INBOUND AND HAD BEEN FLYING THE APCH COURSE INBOUND); HE SHOULD HAVE TOLD ME TO FLY A HDG OF 270 DEGS TO REJOIN THE CTRLINE. I; ON THE OTHER HAND; SHOULD HAVE VERIFIED THE INTENTION OF THIS HDG INSTRUCTION (INSTEAD OF ASSUMING THAT THE PURPOSE OF THE HDG WAS TO BRING ME BACK TO THE CTRLINE).