Hi Barry and welcome,
What the person pointed out, is what is known as "cant" (k-ant).
You are tilting the gun (most likely) in towards your head. This may be because you are pre-mounting the gun, then bringing your head down to the comb. By pre-mounting, you are getting the butt of the gun, comfortable in your shoulder, causing a tilt.
Or, you are tilting the gun over to your face, in order to keep your head upright.
Anyway, try mounting the gun to your face, while looking at a "target", head upright, gun upright, then bring the gun back into your shoulder and see how it feels.
You may benefit from an adjustable butt plate, in order to "cant the pad" rather than the whole gun, and/or to allow you to bring the stock in towards your face a touch more. Though if you have an adjustable comb, this shouldn't be an issue.
Canting the gun,can certainly be a cause of misses.
Somebody here asked the same question, and got a good answer
http://www.ssaa.org.au/competition-info/stories/clay-target_question57-lionel.html
http://www.recoilsystems.com/adjustableRecoilPad/adjustable-recoil-pad.asp